Rescat 37 ENGLISH

37

YEAR 2020

EDITORIAL

Educating in the values of preserving heritage Page 2

INTERVIEW

M. dels Àngels Calvo: science and women Page 3

CONSERVATION–RESTORATION

Collection of Caterina Albert Page 8

Restoration or removal of graffiti Page 20

The first workshop (course/action) in Catalonia Page 38

Dust peeling in a work

by Alfons Borrell Page 42

INNOVATION AND RESEARCH

Altarpiece of Palau-Solità Page 46

Altarpiece of the Corpus of Girona Cathedral Page 56

TRAINING AND KNOWLEDGE Page 62

A MUST-READ Page 65

CONSERVATION-RESTORATION

RESTORATION OR RENOVAL OF GRAFFITI

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Centre de Restauració de Béns Mobles de Catalunya

EDITORIAL

EDUCATING IN THE VALUES OF PRESERVING HERITAGE, A CHALLENGE FOR THE PRESENT There are many well-known examples of anthropogenic aggression on cultural heritage; some are very obvious, easy to denounce, while others are obscured by the message of social protest, as is the case of graffiti used to express a social message or due the artistic value of the graffiti artist in question, but an act which is no less criminal.

In general, our society is not sufficiently aware of the harm that certain attitudes and behaviours cause. The school has so far not been a space for raising awareness on this subject or, at least, not compared to raising awareness of environmental values, a subject on which a great deal of work has been done.

Heritage institutions and art museums, mainly through their pedagogical programmes, have been more dedicated to explaining the importance of art and its context, to encouraging creativity and artistic sensitivity, but a lot of work remains to be done on educating in preserving the values of cultural heritage.

With this in mind, the Centre for the Restoration of Artefacts of Catalonia (CRBMC) has developed an educational programme aimed at primary school

children with activities, such as the "time capsule", which help raise awareness among boys and girls, thus promoting an attitude of respect for heritage and educating children in the most significant causes of its deterioration, so that they understand that it can often be prevented. At the end of the activity, they take home an auca on the most important aspects that have been discussed, This allows their families to know what their sons and daughters have worked on, but also, and very importantly, make them reflect too.

Education is very important in promoting changes in both individual and collective habits and behaviours. Not all problems come from malicious or negligent attitudes; the causes can be many. The case of popular and traditional culture, or religious devotion to images, is also paradigmatic. Examples are needed to understand that certain traditions conflict with heritage conservation. The challenge for the CRBMC, as well as for all conservation and restoration professionals, is to educate people whenever the opportunity presents itself. Let's not give up! Àngels Solé, Director of the CRBMC

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Graffiti on the Palau de la Generalitat in early November 2020.

Photo: Júlia Roca

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INTERVIEW

M. Carme Balliu Badia, coordinator of the Documents, Graphic Works and Photography Department

M. DELS ÀNGELS CALVO TORRAS Professor of Animal Health (Microbiology) at the UAB. Degree and PhD in Pharmacy from the UB. Extraordinary Degree Award. Degree and PhD in Veterinary Medicine from the Complutense University of Madrid (UCM). Diploma in Health and Specialist in Microbiology and Parasitology.

M. DELS ÀNGELS CALVO: SCIENCE AND WOMEN. ITS LINK TO CULTURAL HERITAGE ONE OF THE CLEAREST EXAMPLES OF THE NEED TO COMBINE SCIENCE AND CULTURAL HERITAGE CONSERVATION-RESTORATION IS FOUND IN THE IMPORTANT WORK CARRIED OUT BY MARIA DELS ÀNGELS CALVO AT FROM THE AUTONOMOUS UNIVERSITY OF BARCELONA. IN ADDITION TO SPECIFIC PROJECTS AND STUDIES CARRIED OUT IN DIFFERENT FIELDS, SHE HELPS US IDENTIFY AT A QUALITATIVE AND QUANTITATIVE LEVEL THE MICROBIOTA THAT MAY BE AFFECTING A CULTURAL ARTEFACT OR ITS ENVIRONMENT, AN ESSENTIAL FACTOR FOR ITS CONSERVATION AND/OR RESTORATION Who is M. dels Àngels Calvo?

I finished studying Pharmacy in 1975, and in October of that same year I started working in the Microbiology area of the Faculty of Pharmacy of the University of Barcelona (UB) as an intern while training to be a researcher. In 1983 I joined the Faculty of Veterinary Medicine, which is where I still am.

I have published over 250 research papers. I have collaborated on chapters in mycology and microbiology books. I have tutored 42 dissertations and 35 doctoral theses. I have received 13 awards for my research work and the recognition of the Ministry for the tutoring of industrial theses.

I have carried out research projects nationally and internationally, and have been the lead researcher on several occasions.

I am a full member of the Royal Academy of Medicine of Catalonia, the Royal Academy of Doctors of Spain, the Academy of Veterinary Sciences of Catalonia, the Royal European Academy of Doctors of Catalonia and the Royal Academy of Pharmacy of Catalonia; corresponding member of the Royal Academy of Medicine of Madrid, the Royal Academy of Physicians of Mexico and the National Academy of Veterinary Medicine of Mexico, and member

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of the Medical pharmaceutical Institute of Catalonia, the Argentine Society of Veterinary Medicine and the International Researchers Brotherhood of Toledo.

I have been a member of the Scientific Committee for Animal Nutrition (SCAN) and am currently an expert for the European Commission (EC). I was vice-dean and dean of the Faculty of Veterinary Medicine at the UAB. I am a member of the Advisory Council of the Catalan Public Health agency, vice-president of the Royal European Academy of Doctors (RAED), secretary general of the Academy of Veterinary Sciences of Catalonia (ACVC), vice-secretary of the Royal Academy of Medicine of Catalonia (RAMC) and member of the Governing Board of the Royal Academy of Pharmacy of Catalonia (RAFC). I have six officially approved research programmes and six teaching ones, at the national and regional level. I am an evaluator of different national and international agencies, including the Academia programme of the Ministry of Education and Vocational Training, for access to university teaching.

I have been a professor at the UB and the UCM, and I have taught courses at Ramon Llull University.

I have collaborated in the past and still do so with the Ministry of Culture, the Ministry of Health, the Institute of Agrifood Research and Technology (IRTA), and others.

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Which of your many publications are you most proud of?

Well, I would highlight the following: "Identification of microorganisms that affect documentary heritage" in Libro jubilar: homenaje a Guillermo Suárez, from 2005; Protocols for the prevention, control and treatment of infections by microorganisms that affect the documentary heritage, from 2008; "SEM detection of microorganisms that damage documents and cork material" in Current microscopy contributions to advances in science and technology, 2012, and "Particularities of research work for the final degree project, master's thesis and doctoral thesis” in Com fer recerca: Treball fi de grau, tesi de màster, tesi doctoral i altres projectes de recerca, from 2017.

Your field is biology and, in particular, you work in the Faculty of Veterinary Medicine. How do you get involved in providing analysis, identification and advisory services in the field of heritage artefacts? What was your first assignment in this field?

Many years ago, there was a travelling exhibition of works

by Joan Miró, and its whites ended up becoming multicoloured. At that time I was at the Faculty of Pharmacy, where we were working isolating and identifying fungi, so they got in contact with me. There was also a case of some paintings which were being damaged by fungi, and Josep Maria Xarrié, the former director of the CRBMC, contacted me. And I’ve been doing this ever since. In fact the subject of my Pharmacy's doctoral thesis was the atmospheric microbiota of the city of Barcelona. This topic allowed me to obtain in-depth knowledge about mycology and also environmental pollution from a health perspective, but the knowledge is applicable to all areas.

Which microbiological agents, in general, are most responsible for damaging our cultural heritage?

In the worldmicrobiology, its fungi a without a doubt, because of the lasting damage they cause. But when we perform an analysis, I also like to check the bacterial contamination because it can indicate whether there is any dust, pollution by wastewater, etc.

How important is it to qualitatively identify the species that may be affecting this heritage?

Although the presence of any microorganism can cause problems, establishing the species can help ascertain whether the enzymatic load of the identified microorganisms alters the heritage in one way or another. And I also think we need to bear in mind that, as well as affecting cultural artefacts, they may exist in the surroundings.

They may be aetiological agents that affect the people who have come into contact with the cultural artefact in question, be they restorers or the general public. This effect on health can vary, depending on the species.

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Admission as a full member of the Royal European Academy of Doctors in 2003

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What needs to be considered when disinfesting a cultural artefact?

You would need to know which microorganism is responsible for the problem, but it is just as important, or even more so, to take into account the type of cultural artefact n question and the state of conservation.

What are the main parameters to be taken into account to prevent microbiological damage to cultural heritage?

Without doubt temperature and humidity, not separately, but understood as an inseparable combination of factors that we need to be able to control and stabilize. Repeated changes, even if the variations are small, in these two parameters cause very serious irreversible damage to artefacts. Light can also have a significant impact on the development and maturation of fungi and lead to important chromatic changes in the artefact, which are difficult to eliminate.

How would you evaluate the progress of disinfestation treatments that tackle the biodeterioration of cultural heritage?

I think a lot of progress is being made and in the right direction. The most important thing is the high level of awareness of restorers and their desire to improve on traditional methodologies, without rejecting or renouncing what already works, but taking advantage of everything that is applicable from different fields of science to control the biodeterioration of cultural heritage.

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Working at the CRBMC. About to take an environmental sample in the cleaning and disinfection room of the Documents, Graphic Works and Photography Department, with Esteban Leonardo Arosemena, senior research support technician

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M. Àngels Calvo taking samples

What are the so-called “green methods” for treating cultural heritage affected by microbiological activity?

How often are they applied and how effective are they?

If we understand by "green methods" the use of natural products such as plant extracts or essential oils, I think they can be very useful for environmental quality control, as well as for the diffusive effect they can have on artefacts, protecting them against the growth of microorganisms and the effects of biodegradation. There is also another aspect to consider, which is the activity of certain microorganisms to control those that cause deterioration.

This issue is becoming more widely accepted, and we are testing to see what applications it may have.

What technical and scientific improvements, if any, would you make to the profession of cultural artefact conservation-restoration?

I think it would be useful when training new conservatorsrestorers to include knowledge related to microorganisms that can alter cultural assets, as well as the safety measures involved.

I believe more information needs to be provided on systems for disinfesting, cleaning and preserving these artefacts, fundamentally with regard to anoxia and freeze-drying, among other things, as well with regard to establishing the conditions of conservation after the treatment and for monitoring possible recontamination of the treated artefacts.

More work needs to be done with regard to molecular techniques, such as the application of PCR and methodologies to detect the level of bioluminescence, of ATP, among other things, that may be related to the presence of viable microorganisms. And more use needs to be made of microscopy techniques of all kinds and complexities.

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Currently, what studies at the European and national level, if any, are being carried out on the damage caused by microorganisms to cultural artefacts and their disinfestation? What funds or support is being given to this?

Work is being carried out around the world on bioremediation, that is, using certain microorganisms to displace those that cause damage, and then eliminating them through treatments which prevent the proliferation of both sets of microorganisms.

There also studies being carried out that enable the implementation of molecular techniques that reveal the presence of microorganisms, which cannot be recovered using traditional microbiology techniques.

Methods are also being worked on to detect ATP and to correlate it with the presence of viable microorganisms in the samples analysed.

Funds are available as part of the Horizon 2020 and subsequent projects, to further the conservation and study of cultural and heritage artefacts.

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Close-up of fungi in heritage furniture

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What relationship, if any, does your department in the Faculty of Veterinary Medicine have with other centres that offer the analysis and identification of microbiological activity and advisory services in the field of cultural heritage?

The research group I have the pleasure of leading collaborates with other services and, fundamentally, other research centres, which work on issues related to cultural heritage, especially in terms of microbiological cultures, interpretation of results and advice on the application of control systems, but also on aspects of prevention and drafting of work protocols.

What is the biggest challenge you have faced regarding the impact of microbiological activity on heritage?

For me all cultural or heritage artefacts are important, because they are part of our history. If I had to choose a particular project now, either because its results led to actions or for some other significant aspect, it would be those studies on the stained glass windows of the Sagrada Família, the paintings of Sixena, the mosaics of Empúries, the documentation of the Casa de l'Ardiaca, the paintings of the Barcelona Museum of Contemporary Art (MACBA), the environmental control of the Museum of the History of Catalonia and, more recently, the Filmoteca de Catalunya.

What is your view on the level of biological knowledge of cultural artefact conservators-restorers? Do you think the inherent requirements for our work are currently covered?

As I have already mentioned, I think it would be useful to expand their knowledge in this area and schedule practical classes that would enable a better understanding of the tests and a better interpretation of the results.

It would also be useful if prevention protocols could be established according to each type of cultural or heritage artefact. There is an increasing need for interdisciplinary teams but also, in my opinion, for shared knowledge that allows for more accurate monitoring.

If you had to start over, would you devote your studies, your knowledge and your energy on the same profession?

Certainly. It allows me to bring together two of my great passions: microbiology and cultural heritage, and also to meet a lot of people and make many good friends.

What is the biggest challenge you have faced during your career?

The biggest challenge has been to demonstrate that women, and remember I started very young, can be good professionals. This challenge became more important when I was appointed dean of the Faculty of Veterinary Medicine at the UAB. It should be remembered that this was the first time a woman had ever held this position in a Spanish veterinary faculty.

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What do you think you have gained, if anything, out of this relationship between science and heritage, between microbiota and heritage?

It has certainly been an enriching experience, both personally and scientifically. The world of science, if you’ll allow me to say this, often eschews culture and heritage, and I feel very fortunate to be able to carry out a part of my research in this dual aspect.

It is clear that the current coronavirus 19 (SARS-CoV-2) crisis will lead us to a paradigm shift and increase awareness of any type of infection. We have seen that we are not as strong as we thought in the face of infections... How do you think this crisis will affect us with regard to cultural heritage?

I think that for a few weeks –and I don't really know how long it will last– we haven't been able to enjoy our cultural

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heritage, only through the many videos that have been posted online, which have enabled a significant number of people to experience and enjoy aspects of cultural heritage they were not aware of. I hope this has created a habit which they don’t abandon when “normality” returns, whether things go back to how they were or with a new perspective.

In terms of cultural artefacts as such, the coronavirus has no effect on them. The only thing that needs to be considered is the survival time depending on the type of surface; therefore, if there are people present who have the virus, whether they are asymptomatic or not, they might deposit the virus on surfaces they come into contact with and these would require cleaning, at least, quarantining.

What can we learn from it?

I think one good thing we’ll take from it is an increase in cleanliness and control measures, and, in terms of society as a whole, it’s a lesson in humility. Without the collaboration and awareness of everyone, we cannot overcome the SARS-CoV-2 pandemic. It has completely disrupted our routine and has shown us that there really is no small enemy.

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Taking a sample with a sterile cotton swab from a support affected by microbiological activity

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Ultimately, once the pandemic is under control, we’ll have a huge task ahead which will require us to change and adapt some of our priorities, affecting how we understand sociability, the economy, caring for the elderly, and many other aspects that will have to be addressed. But we cannot lose hope that these changes will help make the world a better place.

Do you think that, as a group of professionals, we will be more aware of the risk of pathologies as a result of being in contact with material that contains microbiological activity?

I would like to think that this awareness already exists, and that the pandemic we are experiencing will ensure we go back to living under the hygienic and environmentally controlled conditions that we should never have stopped living in as a society. I hope that the pandemic has taught us that prevention is vital, and that if the right measures are applied, we can minimize the danger of contamination and alterations caused by microorganisms, in this case, viruses, both in cultural assets and with regard to the health of human beings, animals and plants.

I must refer to your speciality in Documents, Graphic Works and Photography conservation-restoration, which is how we came to know one another... Do you think the state of conservation in this area, often involving a great deal of microbiological damage, will be more taken into account from now on? Do you think there may be a greater focus on its treatment?

Indeed, the microbiological contamination of documents, graphic works and photography, as well as its control and prevention, are what led us to start on this, now, lengthy collaboration that I consider very enriching. I have learned a lot, working with you, as well as with all the conservators-restorers with whom, over the years, I have collaborated in the different areas of cultural heritage.

Of course, although the pandemic is of viral origin and heritage assets cannot be directly affected by viruses, society in general has become aware of microbiology and pathogens, the importance of preventive measures and, even of how changes in temperature and humidity can promote the dispersion of etiological agents. In this regard, I do believe and hope that the degree of awareness in society in general towards the conditions that are conducive to the presence and persistence of a pathogen in a given environment or surface has increased.

Thank you very much, M. Àngels, for your availability, for your collaboration in all the projects proposed to you, for the work you have done and, above all, for bringing science and research closer to the world of heritage.

Thank you to you too.

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Centre de Restauració de Béns Mobles de Catalunya

CONSERVATION-RESTORATION

DOCUMENTS, GRAPHIC WORKS, PAINTING AND PHOTOGRAPHY

Intervention of the collection of graphic and pictorial works of Caterina Albert, known by her pseudonym Víctor Català

CATERINA ALBERT I PARADÍS INCORPORATES MOSAIC (1946) IN HER LITERARY WORK, a collection of autobiographical articles. Dates that take us to her more plastic arts period, which began at a very young age.

Her focus and interest on the plastic arts led her to take painting classes through which she improved her technique. Apart from the historical and aesthetic value of the collection itself, the drawings, which sometimes illustrate the publication of her written works, are considered the precursors to her literary work. Together with her pictorial works, they comprise a great documentary record of the authors memories.

Rarely can such documents be linked and studied in parallel with a writer's career.

In 2018, with the support of the Ministry of Culture of the Government of Catalonia, and financed by subsidies for the conservation-restoration of artefacts, the graphic and pictorial works of the author were restored, which for years had been on display at the Víctor Català Archive Museum, located in Clos del Pastor, in L'Escala (Alt Empordà county). We are currently working on the conservation-restoration of the rest of the collection, including the author's original manuscripts, her epistolary archive and other documents that are preserved in the Historical Archive of L'Escala, in Alfolí de the Sal. GRAPHIC WORK INTERVENTION PROCESS Introduction The intervention of the graphic works consisted of the physicochemical stabilization of 81 works on different media created with a huge variety of supported techniques: graphite pencils, watercolours, gouache, pastel and ink are some of the techniques used by the author on corrugated paper, album sheets and cardboard, among others.

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After registering the collection and ruling out any microbiological damage, it was documented photographically with diffuse, raking and ultraviolet (UV) light in order to provide graphical proof of its original state of conservation and at the time of its intervention.

State of conservation The graphic works as a whole suffered damage from the intrinsic alterations derived from the ageing of the basic material, the adhesion of the original supports to secondary supports by means of different types of adhesives and the acidity derived from the material used for the presentation system.

As a result the base material was visibly deformed, with undulations derived from the original presentation system, widespread yellowing and the effects of oxidation in certain places

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Preliminary study of the collection of graphic works with measurements of the pH and conductivity of the bases.

Photo: Elisabeth Carvajal

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M. Carme Balliu, conservator-restorer, coordinator of the Documents, Graphic Works and Photography Department Maite Toneu, conservator-restorer, coordinator of the Painting on Canvas Department

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Portrait of Caterina Albert's maternal grandmother, after the intervention.

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Portrait of Caterina Albert's maternal grandmother, before the intervention.

Photograph with raking light.

(foxing), along with rips along the edges. As for the supported layer, it was affected by fading and occasional losses, as well as the localized alteration of metalloacid inks used by the author in some of her caricatures.

Intervention The wide range of base materials and artistic techniques applied required specific stabilization treatments for each piece. However, based on an organoleptic examination, a macroscopic observation of the works (45x binocular microscope), a preliminary physicochemical study of the stability and solubility of the supported layer and from measuring the pH and conductivity, various general intervention processes could be defined.

First, the works were mechanical dry cleaned, mostly on the back and respecting the codicological features identified. Subsequently, the self-adhesive tapes were removed and the secondary supports were detached, followed by the chemical cleaning of the base material using different application methodologies, depending on the supported technique and the results of the preliminary study.

Sontara® was applied through capillarity on Oita phenolic plywood with a buffer solution of

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Portrait of Caterina Albert's maternal grandmother, after the intervention and framed for display

sodium citrate with a pH of 6, and adjusted to the appropriate conductivity of the supports; a suction table and ultrasonic spray was also used, applying semi-rigid agar-agar gel and Gellano® semi-rigid gel.

As soon as the supports were clean and stabilized at the dimensional level, the consolidation of tears and material reintegrations continued with applications of Japanese paper of different types of fibre and weights, adhered with wheat starch paste or a cellulose ester based adhesive.

Part of the collection was prepared for framing with the pieces mounted on conservation cardboard, with passe-partout and glass suitable for a museum and with filters to minimize the effects of the UV light. The rest were arranged in preservation envelopes and boxes, following the specific preventive conservation guidelines for proper storage and/or display. Factors such as storage in drawers or other storage devices, temperature and humidity control and exposure to light will need to be taken into account in order to ensure the preservation of the set of works, some of which are currently on display in the Sala Víctor Català, in the Alfolí de la Sal Historical Archive, in L'Escala.

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Landscape before the intervention with damage to the canvas base

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Illustration by the author, Caterina Albert, for the literary work Solitud, before the intervention

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The work after the intervention

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Illustration by the author, Caterina Albert, for the literary work Solitud, after the intervention and framed for display

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PICTORIAL WORK INTERVENTION PROCESS Introduction The pictorial collection by Caterina Albert is made up of paintings using oil on canvas, with diverse themes: full-length portraits of people and their relatives and friends, still lifes and landscapes from where she lived.

State of conservation Prior to the intervention, the state of conservation of the pieces varied from regular to deficient.

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Most of the damage and deterioration can be summarized as follows: attacks by xylophagous insects on the wood of the strainers and frames; dirt and dust, both on the front and on the back; deformations of the fabric as a result of lost wedges and rusting of the studs that pierced the fabric at the contact points; small holes in the fabric caused from human intervention; cracks in the pictorial and preparation layers, and loss of these layers in certain points.

It is worth noting that several works displayed some bleaching in areas of the pictorial surface.

Although these were more visible where there were dark colours, such as black, we also found them in areas of other colours such as red and various ochres. This form of bleaching was analysed and studied with by chemists at the centre. Based on these analyses and the scientific information consulted, it seems that the bleach-

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The work after the intervention

Portrait of a woman from the waist up in front of a mirror, before the intervention, with bleaching caused by the metal soaps

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Portrait of a woman sitting wearing a mantilla, before the intervention, with deterioration caused by metal soaps and localized losses of the pictorial and preparation layers

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The work after the intervention

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ing is caused by the migration of metal soaps on the pictorial surface. This type of deterioration was found in several large paintings (CRBMC registration numbers 13592 to 13596 and 13600).

One possible cause is exposure to environmental conditions with low temperatures and high relative humidity. Another cause could be due to certain technical characteristics, such as the presence of the binder oil, the white lead, and the fact that these works do not have a layer of varnish.

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TABLE OF ANALYSIS AND RESULTS CRBMC reg. no. 13600 Location where sample was taken:

Analytical technique. Summary of results M1. µFTIR spectrometry The whitish alteration is composed of calcium carbonate CaCO3.

Key – Sample M1 – CaCO3 pattern

Taking sample M1

M1: White spots M2: Blue of the skirt M3: Red of the chair

M2. µFTIR spectrometry and stratigraphy

Key – Sample M2 preparation – CaCO3 pattern – White lead pattern

Taking sample M2

Polychrome

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Blue

White lead, lead carboxylates, oil

Polychrome

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Black

Unidentified

Preparation

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White

White lead, CaCO3

Support

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Yellow

Bast fibres

M2. Stratigraphy at 200x magnification with UV light

M3. µFTIR spectrometry According to the μFTIR analysis, the sample is composed of white lead and red ochre bound with oil given the formation of lead carboxylates located at 1.530cm-1, which are formed during the ageing process of the oil.

Key – Sample M3 – White lead pattern – Red ochre pattern – Pic subs. lipídica – Lead carboxylate strip

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Taking sample M3

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TABLE OF ANALYSIS AND RESULTS CRBMC reg. no. 13609 Location where sample was taken:

Analytical technique. Summary of results Fibre comparison M4 and M5. Optical microscope.

M4

M5

Location of M4 and M5 Fibres a 200 augments

M4. Vertical thread M5. Horizontal thread M6. White from the shirt collar area M7. Efflorescence

The fibres of the support fabric are bast fibres, probably linen, given the existence of knots and dislocations.

μFTIR spectrometry. Comparison of M6 and M7.

Key – Sample M6 – White lead pattern – Pic subs. lipídica – Lead carboxylate strip

The white polychrome of the shirt collar is composed, as in the other paintings, of white lead 2 PbCO3 · Pb(OH)2 and lead carboxylates bound with oil.

M7. Sample of white efflorescence from the black area of the dress.

As for the whitish efflorescence found in seven of the paintings in the collection, these are composed of lead carboxylates. These compounds are formed within the pictorial layer, as a result of the ageing of the binder (oil), and migrate to the surface. These processes of formation and migration may be accelerated by the humidity and temperature conditions to which the work is subject. The use of a strong enough complexing agent is recommended to dissolve these lead salts and they can be kept at bay by applying rigid agar-agar type gels here and there as required.

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TABLE OF ANALYSIS AND RESULTS CRBMC reg. no. 13610 Location where sample was taken:

Analytical technique. Summary of results Fibre comparison Optical microscope. Stratigraphy. μFTIR spectrometry M11

M12

Fibres at 200x magnification

The fibres of the support fabric are made of linen.

M.11. Horizontal thread M.12. Vertical thread M.14. Blue paint

M14. Capa de preparació

Key – Sample M14 – White lead pattern – CaCO3 pattern Taking sample M14

Pel que fa a la preparació, aquesta es compon de blanc de plom i carbonat de calci possiblement aglutinats amb oli.

M.14. Capa pictòrica, color blau.

key – White lead pattern – Prussian blue pattern – Lead carboxylate strip

As the spectrum shows, this blue polychrome is composed of white lead 2 PbCO3 · Pb(OH)2, Prussian blue and lead carboxylates bound with oil.

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Polychrome

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Blue

White lead, lead carboxylates, Prussian blue, oil

Preparation

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White

White lead, CaCO3

Support

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Yellow

Bast fibres

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Photographs of the work environment, with the conservatorsrestorers and the chemist of the CRBMC

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Close-up of two of the consolidation treatments located on the canvas base

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Intervention The conservation-restoration process was aimed at stabilizing the works and also improving their readability. The whole intervention was based on the criteria of minimum intervention and maximum respect for all elements.

Based on the preliminary diagnosis carried out and the proposed intervention, each work was prepared in situ for transfer to the CRBMC. Bubble wrap, sealing tape, registration number labels and gloves were used to pack up the works.

A worktable was set up and the team worked together. The procedure followed involved a visual examination to diagnose the condition, the removal of the loops for hanging, vacuum cleaning of the dirt deposits with the help of a brush, temporary attachment of the loose wedges using adhesive tape, temporary attachment of the edges of the canvas to the frame, separation of the frame and the canvas where it was loose, packaging with bubble wrap and masking tape and adding visible labels with the register number. Finally, the paintings were spread out, in their natural position, leaning against the walls of the room. With the materials available, the works were insulated from the floor (plastic box covers and bubble wrap) and cardboard was placed between the paintings, as protection for the support.

Once the works were transferred to the CRBMC, they were disinfested and disinfected in an anoxic chamber, where they remained for 25 days, with an atmosphere of 0.01 ppm oxygen.

They were documented by taking photographs using diffused light, raking light, UV and IR in the

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Close-up of two of the consolidation treatments located on the canvas base

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Portrait of Mila, from the literary work Solitud, before and after the intervention.

The protective frame is missing

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case of some of the works. A more detailed diagnostic examination was carried out with samples extracted for physicochemical analyses, before and during the intervention process.

The sequence of treatments applied to the paintings was, in general, as follows: localized attachment of the areas of the pictorial and preparation layers that were coming loose, by brushing on Aquazol® 500 adhesive, 3% or 5% in distilled water or ethanol.The dirt and dust on the back of the canvases, and between the canvases and the frames, was cleaned by vacuuming. and using a flat brush The wood of the frames was also been cleaned with distilled water and ethanol (1: 1). The consolidation of the canvas support was carried out in a localized manner, small tears were sewn up and grafts of linen were applied with preparation in the holes where the studs were. The adhesive used was sturgeon glue (20%) and wheat starch (10%) in a 1:1 ratio. The weakened fabric of the edges was reinforced with Tetex® (synthetic gauze) and Beva® 371 as an adhesive. Deformations were reduced by applying

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During the aqueous cleaning process

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Still-life painting.

Before the intervention, photography with UV light and photography of the painting once restored

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pressure and a bit of moisture, the loose fabric edges were attached with stainless steel staples, and missing wedges were replaced. The rust of the studs was treated mechanically (with Dremel®) and a solution of 3% tannic acid in ethanol was applied to them.

The pictorial surface first underwent a dry clean with a flat brush and a vacuum cleaner to remove superficial dirt and dust. Where it was deemed necessary, this continued with an aqueous clean based on the results of solubility tests and pH and conductivity measurements, according to the CRBMC’s cleaning protocol for pictorial works. In the case of the work Still life with fish (CRBMC registration number: 13591), the aged varnish was removed, a second phase of cleaning with solvents was carried out with the AE3 mixture of the cleaning test with solvents (25% acetone and 75% ethanol) and a final aqueous phase of cleaning was necessary.

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Portrait of a man before the intervention. The bleaching caused by the metal soaps is visible

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The work after the intervention process

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As for cleaning the areas bleached by carboxylates, the metal soaps, the process was studied and agreed with the centre’s chemists. As a case study, in the most affected painting, Portrait of a man with a boil (CRBMC registration number: 13609), to reduce the surface bleaching caused by carboxylates, it was cleaned with trisodium EDTA of the brand Fluka®, at 5% in a buffer solution with a pH of 6.5 and gelled with 2% methyl cellulose. The EDTA was used to control the performance on the surface. Tests were carried out using gels with agarose (rigid gel) and methyl cellulose, and the second option was chosen, allowing the gel to act for 2 minutes on the surface. Finally, a layer of Laropal® A81 low molecular weight varnish at 20% and Shellsol® A and D40 (35:65) was applied, which improved the readability of the work.

The final presentation system of the losses on the pictorial and preparation layers has consisted of filling in the gaps with traditional putty made from animal glue and calcium carbonate. The pictorial reintegration followed the principle of creating an illusion, using watercolours and/or Gamblin® paints and pigments bound with a low molecular weight resin.

As a preventive conservation measure, all the backs of the paintings were protected by applying Tyvek®1442 attached with adhesive strips. The holes in the wood of the frames and strainers, caused by the attack of xylophagous, were sealed with wax. Also, in agreement with those responsible for the collection, it was decided that some of the paintings should be framed and protected with methacrylate with a UV filter. Priority was given to the paintings where large areas of the preparation layer was clearly visible, to prevent darkening from environmental pollutants. The recommended environmental conditions to keep

the works stable are: relative humidity: 45-60% (maximum daily variation: 5%); temperature: 18-22ºC (maximum daily variation: 2ºC), and lighting: maximum 200 lux, free of infrared and ultraviolet radiation. Where there are light-sensitive organic shellac pigments, lighting levels should be reduced to 50 lux.

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Back of a frame without protection and once applied

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DETAILS GENERIC CLASSIFICATION: documents, graphic works and photography; painting on canvas | OBJECT: 105 works (81 graphic works and 24 pictorial works) | MATERIAL/TECHNIQUE: graphic works: paper and/or parchment (base material). Graphite, charcoal, pastel and others. Pictorial works: oil painting | DESCRIPTION: various | AUTHOR: Caterina Albert i Paradís, known by her pseudonym, Víctor Català (l’Escala, 1869-1966); Joaquim Folch i Torres (Barcelona, 1886 -Badalona, 1963); Y. Riera (?) and Manel Rocamora (Barcelona, 1892-1976) | DATE/PERIOD: graphic works: 1877-1932. Pictorial works: 1880-1890 DIMENSIONS: various | ORIGIN: Víctor Català Archive Museum. Clos del Pastor, l’Escala (Alt Empordà county) | LOCATION: L’Escala Historical Archive, Alfolí de la Sal, l’Escala (Alt Empordà county) | CRBMC REGISTER NO.: 13517, 1359113604 /13607-13616 | COORDINATION: graphic works: M. Carme Balliu; pictorial works: Maite Toneu | RESTORATION: graphic works: Ariadna Garrigolas and Francesca Tort, with the support of Elisabeth Carvajal and Anna Ferran; pictorial works: Maria Brossa and Irene Panadés | SCIENTIFIC PHOTOGRAPHY: Víctor Illera and Ramon Maroto | ANALYSIS TECHNIQUES: Ruth Sadurní and Ricardo Suárez | ANOXIA: Pep Paret | YEARS OF RESTORATION: 2018-2019

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CONSERVATION-RESTORATION

WALL PAINTINGS

Restoration or removal of graffiti a dicotomy in cultural heritage conservation

THE MATERIALS EMPLOYED IN THE CREATION OF GRAFFITI ARE GENERALLY UNORTHODOX, of limited durability and highly aggressive: from a conservation-restoration point of view this presents us with two major, contradictory problems. On the one hand, the conservation of exterior graffiti of cultural value and, on the other hand, the removal of graffiti considered to

be vandalism, especially when located on the walls of historic buildings, monuments and sites.

The existence of this antinomy within the same artistic typology provides a unique case in the world of conservation-restoration. As a result one must look for solutions both to the preservation and to the elimination of the same element, with good reasons to justify either approach.

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Portrait of an old man in the village of Penelles (Noguera county) created during the Gargar festival, an example of rural street art.

Sabotaje al Montaje, 2016

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Pere Rovira, coordinador de l’Àrea pintura mural i escultura en pedra i jaciments arqueològics

Introduction Graffiti is a popular contemporary inscription, drawing or painting usually made on the walls and surfaces of public spaces. Due to its technical characteristics and two-dimensionality, it is classified as a wall painting. The International Council on Monuments and Sites (ICOMOS) states: “Wall paintings have been cultural expressions of human creation throughout history, from the earliest beginnings, such as rock art, extending up to present day murals. Their deterioration, accidental or intentional destruction constitutes a loss affecting a significant part of the world’s cultural heritage” (ICOMOS, Principles for the preservation and conservation/ restoration of wall paintings, adopted at the 14th General Assembly of the ICOMOS in Victoria Falls, Zimbabwe, October 2003).

The word graffiti is used both to describe epigraphic inscriptions of archaeological origin and to refer to a drawing on a wall. The term graffiti is Italian, the plural form describing a scratch on a surface made with a pointed object (from the Latin graphium). It has come into usage in its Italian form throughout the world to mean a free and creative inscription or drawing on a wall (except in Italy, where the English term writing is used). The TERMCAT, Terminology Centre, defines graffiti as an “inscription or anonymous painting

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The Shark of Carmel, in Barcelona, is a large mural by the renowned graffiti artist Blu, an Italian artist who, like Banksy, remains anonymous. It was created on the occasion of the Influencers 2009 festival, organized by the Centre for Contemporary Culture of Barcelona (CCCB). This work has severely deteriorated over the years; the green colour has faded especially

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Graffiti as a concept and technique has always existed, if we bear in mind how a rock painting was created in comparison to a modern work of graffiti.

Levantine cave paintings, in the Abric d’Ermites in the Pietat mountains (Ulldecona, Montsià county)

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Big road constructions with large concrete walls have become optimal spaces for graffiti artists

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A typical sprayed graffiti signature (Tag)

of fast and spontaneous strokes, made on walls in public spaces”. This represents only one type of graffiti. Graffiti also refers to the “inscription or drawing done in a place visible to pedestrians, such as a wall, a door or a monument ”, a definition which better covers the technical possibilities within this creative world.

Graffiti in modern art arises in a marginal context, from social or political tensions, through spray painted signatures on walls (tags). It has emerged as an artistic manifestation of counterculture, and is understood to be an organized sociological movement against the established orthodox system. These marginal works of graffiti, considered vandalism, are aimed solely at giving their authors with visibility, in a race to achieve maximum dissemination through their signature. However, they also include social comment, messages and insults aimed at people and the ruling classes.

As it has evolved, this type of written manifestation has subsequently drifted towards a more complex artistic expression, with a certain aesthetic taste, becoming a fully manifested work of cultural value in the first decade of the 21st century. Since its initial cultural anarchism, graffiti has spread uncontrollably to encompass all materials and all surfaces with a sufficiently flat area, in the exterior and interior public spaces of towns and cities.

Early graffiti or tags were rather different from the concept and shape of the graffiti which has been produced from the 1990s onwards. Due to its cultural and creative basis, this new wave of graffiti started the artistic movement Street Art, known in this country as "urban art", as it forms a part of street culture. Although some scholars grant it the same importance, graffiti understood

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A graffiti signature (Tag) evolving towards a more artistic concept

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The art of graffiti often involves a visual game with the architectural environment as can be seen in this graffiti in Penelles. Photo: Aleix Barberà

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It deteriorates very quickly due to its location outdoors and on unprepared surfaces, and also due to the type of paint used

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as wall painting is only one part of urban art, an art form which encompasses all the diversity of artistic sensibilities, involved directly in its surrounding society and landscape. Some artists have gone beyond graffiti in their wall painting, and their works are best described as what we might call “mural construction" due to the large format of the pieces and their creation within a workshop setting.

Graffiti as a concept is linked to its surroundings, and its conservation and deterioration must be considered within this changing environment, in itself something that should prevent its preservation and possible extraction. If we are to be consistent, graffiti should follow the same evolution and progression over time as its environment, in terms of conservation. From this point of view, graffiti is an ephemeral art. Graffiti is an existential reality, and while there is no official regulation established for its preservation, that does not mean we should not consider the importance of working towards its protection and conservation.

We have progressed from the vandalistic tag to creative wall paintings, which have transformed some towns and cities into genuine open air museums. However, many examples of graffiti have never lost their essence as forms of social commentary and critique, and rightly so. Graffiti is both a social and an artistic phenomenon.

Cities with a modern social perspective want to be on board with culture and new cultural movements. It is for this reason that urban art fills a gap in the plastic arts, generating cultural movement in the streets, and self propagating and spreading through social media. What was originally a phenomenon reviled and rejected for its marginal, illegal and vandalistic nature, as propaganda and political criticism, has been transformed by graffiti artists into an admired and sponsored art.

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In the boundless gallery that represents the urban, and more recently the rural, environment, graffiti has been extended to include any human construction or fabrication that can be decorated in this way. There is no longer an explicit procedural limit, but instead an absolute freedom of creative and material expression, without borders.

This is something which, indeed, characterizes the contemporary arts. This also results in an incredible artistic range; from the simple, poorly made and monochromatic signature (tag) to the large scale socially critical, technically complex and polychrome murals that decorate large buildings or are generated by Land Art. The list of graffiti artists is endless, as the dynamics of the movement grows and new and talented authors come to light every day, especially through social media.

In fact, there is currently no city in the world that does not have graffiti, whether artistic, critical or vandalistic. In most cases graffiti in the form of large scale murals decorate and characterize a public space, street, building or social entity where they are located, conveying an artistic and socially responsible significance, whilst sometimes moving away from social criticism and becoming more a form of advertising and decoration. However, we must distinguish between what is the decoration of a space and what is urban art, and not confuse the two.

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Graffiti as a technique and concept allows it to be painted on any surface or construction, regardless of its function

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There are as many base materials for graffiti as there are types of surface and objects in urban environments, covered, or uncovered. The peculiarity of the work’s openness to the public provides it with a permanent visibility, but also conditions its short and long term conservation.

More often than not graffiti is integrated within a constructed element. As a result it can be defined as an immobile mural work; it is technically difficult, and sometimes impossible, to remove.

Whilst at the technical level this reality may not condition the piece of work, at an administrative level it can represent a legal issue as it is necessary to determine the legality, ownership and civil liability of the piece, aspects that in many cases are not defined. As a result, both law and duty of conduct may be violated.

The challenge of quickly painting a surface in an outdoor urban environment necessitates the use of agile format techniques and easy-to-apply materials with accelerated drying. This automatically becomes a contradiction for conservation.

The most common way to paint a graffiti is to paint it directly on a surface, but we can find countless artistic variables, from spray to collage to montage. Due to the type of materials that make up a piece of graffiti and its base, most cannot be kept in place for a long time without some irreversible exponential deterioration, a fundamental aspect to be considered when, as

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Graffiti as a concept is a finite art. External moisture and the proliferation of biological agents cause a rapid alteration in the graffiti that is difficult to remedy

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As a form of contemporary mural art, graffiti can be made up of infinite methods of expression and materials that make its attractive and at the same time vulnerable.

Photog: Jon Tyson (©Unsplash)

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conservators-restorers, we consider preservation and preventive conservation measures. In fact, if we are realistic, both technically and conceptually, a work of graffiti is not something that can endure in time.

Graffiti treatment: conservation or removal As previously stated, due to the ephemeral nature of its character and material, graffiti should be left to follow the evolutionary deterioration accorded by its location and the paint used. We should not interfere in its preservation. Graffiti tends to disappear after a few years, fulfilling the role of this type of artistic manifestation as a temporary art.

The conservation of exterior graffiti The first problem is how to preserve these murals in the long term, as they are usually located in unsustainable environments and made with degradable industrial materials (not made to last outdoors).

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When a city has itself requested, paid for and promoted the murals which have been painted, and has incorporated them into its identity, then the deterioration of said murals becomes more of a concern. The authorities don’t want the area to appear unmaintained, or be seen to have little interest in the conservation of art and, consequently, the culture it promotes. This is even more significant when artists and their graffiti move lose their anonymity and become known within the contemporary art world, when they are admired and exalted through social media (essential tools in the recognition of graffiti as art). In these cases graffiti becomes a work of art appreciated at a social level and valued by its cultural environment. It is appreciated not only by historians, gallery owners and promoters of contemporary art, with whom exhibitions are organized in contemporary art museums, but above all by the cultural and political representatives of the municipalities interested in integrating this culture into their urban panorama, as seen in the case of the urban art festivals.

If a known artist's graffiti appears in or is located in a city, care must be taken to preserve it properly. Even more so if it has been specifically commissioned. This means preserving the work within the limitations of the institution that has to manage it and, where necessary, stabilizing it with a traditional system of conservation-restoration and preventive conservation, without forgetting the need to photograph, document and record all graffiti systematically, old and new, as we would (or should) do with public street sculptures.

In the same way, historical graffiti with a certain social relevance, painted in emblematic areas, is also appreciated for its significance.

This is the case, for example, with the blocks that were part of the Berlin Wall, some of which are still preserved at the original site (East Side Gallery), whilst others have been integrated into a museum.

It is particularly important that artistic graffiti is not painted on a protected historic building, monument, or archaeological site, as this would lead to a conservationist dilemma that would logically end up taking the side of the monument.

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In fact within the code of ethics that they themselves have established over the years, graffiti artists try not to paint on cultural monuments or buildings, since their purpose is not to destroy but to create, and to respect. And the town councils themselves, some of which act also as festival promoters, respect this. They look to enable urban art to socially and culturally enhance public spaces, usually in disused areas and buildings or those adapted to this specific use.

Although many graffiti artists already consider the nature of their work to be ephemeral, and even promote this, their art ends up giving meaning to an environment and conditioning a cultural landscape that the city subsequently does not want to lose. Therefore, the very reality that characterizes this urban art, together with the artistic recognition of the authors and the tourism appeal of their work, necessitates its long-term conservation and makes its conservation-restoration and preventive conservation obligatory. It needs to be carried out, as previously stated, in collaboration with the artists during the creation of the work, with an appropriate selection of the paint to be used and the right preparation of the area to be painted.

Conservation of graffiti in situ An exterior wall painting, as we know, is always difficult to preserve long term, especially when there has been no prior preparatory groundwork.

If we do not want the graffiti to rapidly deteriorate, we have two options for the preservation of these wall paintings: in situ conservation (which involves preventive conservation, continued maintenance and the sporadic restoration) or the removal of the wall painting (its transfer and subsequent placement in a museum or in a suitable exhibition space).

For in situ graffiti conservation, as previously stated, there are two key factors to bear in mind: the preventive conservation of the site and the restoration of the work itself when necessary.

Obviously, these interventions must be carried out by conservators-restorers specialized in wall paintings, through a previously planned conservation-restoration and preventive conservation project.

The first form of in situ conservation of graffiti involves adopting complex measures of preventive conservation for the site, although this is not always possible, as the environment may have too many variables (variables completely different from those found in a museum). The

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most obvious immediate solution is to construct a roof, basically to prevent direct rain damage, and to construct physical barriers to prevent people from getting close and interacting with the work, thus limiting direct access to the site.

But often these minimal interventions are impossible to achieve, not only due to the location, but also because of the monumental nature of the work or because said implementation would harm the building in question, which may be protected by law.

The maintenance of the building where the graffiti is located and its environment must also be taken into account. The owners of the building should be responsible for preventing biological proliferation and for its maintenance. The building owners or owners of the site of the wall painting may see the graffiti as a degeneration of the environment and may wish to remove it, especially if they did not give permission for it in the first place. Therefore, properly educating the owners and providing help in maintaining the graffiti is essential.

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Graffiti artist paints any public space they can access, such as this wall of the church in Plaça dels Àngels, Barcelona

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Underground footpaths and subway spaces are areas where graffiti has proliferated. Photo: Paul Murphy (©Unsplash)

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Any exterior surface is susceptible to being graffitied.

From its beginnings, graffiti has been painted quickly on trains when they stop (backjump), which then become a travelling form of urban art. Photo: Fatih Yuur Ggjo (©Unsplash)

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While preventive conservation will often not provide the required solutions in an exterior space, some form of intervention must be carried out on the graffiti from the beginning to avoid its rapid deterioration. In Leipzig, authorities have placed a glass partition over the Madonna with Child mural by Blek le Rat, after its restoration, to prevent damage. But these types of protections made of glass or methacrylate require permanent maintenance to prevent them from getting so dirty that they obscure the artwork.

Conservation also has legislative implications.

Public graffiti considered to be of historical or artistic interest should be protected by law and regulated, making the allocation of public resources easier. Thus, for example, Muelle’s graffiti, based on the identity and events surrounding the Movida movement in 1980s Madrid, is under consideration as a BIC (asset of cultural interest), since this work is pioneering in Spain.

Preventive work on the environmental and cultural surroundings of graffiti is very important, but a curative conservation and restoration intervention will almost always be required at some point. The conservation-restoration of graffiti in situ must follow the same criteria, scientific line and traditional restoration procedures which would be applied to any exterior wall

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Graffiti artists use the space needed to express themselves and work with the elements of the building, regardless of the material.

Spray cans are very suitable for this purpose

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painting, and must be carried out by specialists with an official degree in conservation-restoration. We will not go into detail regarding the requirements that must be followed in the conservation-restoration of graffiti as a wall painting in situ because they are the usual ones; from the documentation and technical study to the final intervention report, including the required agreed or approved conservation-restoration plan. Since these murals are located on the street, on walls, sometimes on a large scale, requiring scaffolding or cranes, the relevant legal permits and liability insurance must be up to date, and current regulations on vertical work and health and safety regulations for workers must all be complied with. It is also important that the owners of the building and the artist are informed of what needs to be done, and above all that they are asked for their approval and, if necessary, for their collaboration.

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For the preservation of graffiti, apart from preventive conservation and conservation-restoration, there must be an adequate and continued maintenance. Regardless of the work required in specific cases, the most viable approach for areas with many murals is to create teams of conservators-restorers which specialize in the maintenance of the murals and the spaces they occupy (as currently seen in central London), and that can deal with surface cleaning and minor, one-off interventions, where necessary. Although in the long run the graffiti will deteriorate, at least we will have control over its state of conservation.

Regardless of the preventative conservation measures, and in view of the reality of the situation, a solution that can be adopted to help with the durability of graffiti in situ directly relates to the paint being used, either through the manufacture of more resistant paints or through the protection of the mural surface. We

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do not believe that obtaining industrially manufactured paints made specifically for graffiti artists will be possible if there is no significant market demand, although homemade paints can be used, as can the resistant, silicate-type paints that are currently available on the market, although these are expensive and have a limited colour range.

The option of adding film-forming layers such as a protective varnish to the paints surface, to insulate the paint from the environment, is a possible conservation solution. However, many of the commercial products that can be used, such as varnishes or synthetic resins, do not usually give good results in the short term, as they are not designed for this purpose. In the face of the deterioration of Meg Saligman's murals in Philadelphia, a few years ago Dr Richard Wolbers, interested in their conservation and seeing that the traditional methods of restoration adopted had not yielded good

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results, conducted scientific studies to find a film-forming, breathable, transparent and easily renewable product that could be applied to the murals surfaces to protect them from the outside environment. The resulting product used a base of polyacrylic acid (a product from the pharmaceutical industry used to covers pills to protect the stomach after ingestion), which when mixed with an acrylic resin and with the proper formulation, produced a very suitable protective layer. This offers very good results when properly applied as a layer of varnish on top of graffiti, and can provide a solution to temporarily prevent the deterioration of the graffiti. There are also new products made from nanoparticles used to protect mineral surfaces. These are water repellent and maintain water vapour transmission and may possibly be of use to protect graffiti.

Where a conservator-restorer’s professional ethics and conservation criteria allow for a

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The Philadelphia Muses graffiti is part of the street art of the city of Philadelphia and has become an iconic image of the city.

Meg Saligman (2013). Photo: José Antonio Gallego Vázquez (©Unsplash)

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A graffiti artist at work. It usually has to be done quickly and in an uncomplicated manner, regardless of the surface

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The poor urban suburbs of large cities are graffiti hotspots

— complete restoration, in the face of irreversible deterioration, a partial or total repainting of the mural, with the same materials, and wherever possible by the artist himself, could be considered an option, as has been done in Philadelphia and other cities. Faced with the irreversible deterioration of a work of graffiti, this can provide a good solution in order to maintain these murals in a permanently good condition.

Problems arise when the artist is no longer alive or when they, or their representative, believe that the work should not be recreated.

Faced with the irreversible deterioration of a work of graffiti, we can make philological restoration the main criterion for conservation.

This happened in Barcelona, with Haring’s lost work Together We Can Stop AIDS. Created in 1989, located in the Raval (where the Filmoteca is now located), this was a gift from the artist promoting the fight against AIDS. Despite having been restored, this 34 metre long mural was destroyed in 1992 during the urban development frenzy of the Barcelona Olympics. Fortunately, due to the type of paint used, it was possible to recreate it exactly in 2014, outside the MACBA. At the time of the restoration a copy had been made and the details of the painting and colour recorded (thanks to the insistence of the restorers Mercè Marquès and Clara Payàs).

An exact reproduction is not always easy to achieve. This depends on the stylistic complexity of the work and, above all, whether it has previously been printed to scale or has been thoroughly documented technically and photo-

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graphically, when possible digitally, with a photogrammetry or 3D scanner. If it cannot be directly reproduced as a wall painting, given the technical difficulties and the location, there is also the possibility of reproducing it at its original location by means of a photographic print (Papelgel®) or with video projection mapping, although it can then no longer be considered an original painting but rather a reproduction.

In any case, the conservation of graffiti by known artists in situ presents an important problem in the long term, one which is still unresolved, not only because of the difficulty of preserving certain materials on certain external

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surfaces, but also in terms of how the graffiti can then be curated. At the same time, we must not forget the management of graffiti as physical and intellectual property; another battle in a basically anarchic and often illegal art form, alien to any commercial market, and in which the authors themselves have an interest in their work being ephemeral, as a form of critique.

Graffiti removal and transfer When the graffiti of known artists begins to deteriorate, and all conservation solutions in situ have failed to halt this damage, it may be necessary to consider the removal and subsequent transfer of the piece to a new support. Deciding whether or not art like graffiti should be preserved requires a lengthy discussion and detailed investigation, which cannot be done here.

But the reality of the situation is what we see happening to some works by Banksy or Invader.

Popularity and international recognition have attributed a monetary value to these murals, leading to some of these pieces being removed and sold to gallery owners. Despite not having the author’s permission, the fact that they fell within a legal intellectual property loophole involving unauthorized and public pieces of work, meant that they went for very high prices. This reality in the work of Banksy and Invader will extend to other authors and will result in a dispute over the removal of graffiti if we do not find a way to legally define it.

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An urban environment can be unified and distinguished by a work of graffiti even when the surface material is uneven. Photo: Ramon Maroto

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Banksy's social commentary works of graffiti, using stencils, have become worldfamous works of art. Photo: Jon Tyson (©Unsplash)

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Regardless of financial implications, graffiti on a stone, cement or concrete surface should be removeable with more or less solvency, so long as there is a minimal pictorial surface with which to work. This includes all types of built up, moderately flat constructions, such as walls or similar surfaces, highway pylons, fences, retaining walls, etc. But not all such surfaces are of smooth construction. If they are sequential planes, irregular, or not compacted (like a wall of brickwork or exposed brick), this complicates the methodology of removal and does not allow a linear extraction, especially with the plastic paints that are used in graffiti. For anything other than a fresco, removal is very complicated.

Also, within this endless universe, a lot of graffiti is produced on surfaces other than chopped stone or masonry, and its extraction is conditioned by the type of base material, size and location of the work, aspects which we will not go into here because of the disparity of potential supporting elements (street furniture, sculptures, iron structures, bridges, doors, railings, glass, trains, vehicles, etc.)Mostly, these works of graffiti degrade along with their base, and in their original location. However, the possibility of moving this supporting base or element, even if only partially, should first be assessed.

Returning to graffiti located on surfaces with the possibility of removal, the only real options

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Many artists at some point in their careers have created street art; this is the case of this work by Perico Pastor in the Casa dels Xuklis, in Barcelona, made with wallpaper stuck to the wall.

Photo: Aleix Barberà

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are the three traditional removal methods, which are strappo, stacco and stacco a massello. None of these three methods of detachment should be ruled out, adapting the methodology to the type of paint with which the graffiti has been produced and the characteristics of the base material.

Despite the disparity of painting materials and techniques used in wall paintings, as long as the paint layer consists of a minimum thickness of pictorial film removal will always be a possibility, depending on the roughness of the surface and the paint’s penetration of the surface.

Without doubt many works of graffiti will never be able to be removed, either because they are deeply integrated into the wall face, because of their size or because they have been created on a very irregular and discontinuous surface. In addition the use of collage and the incorporation of fabrics and papers into painted graffiti (or even made in the workshop and then added, as Swoon, Saligman, and St. Fort do), makes removal more complex, as the irregularity of the surface and the disparity of materials increases, even if the wall itself is uniform.

Regardless of the procedure behind the painting, if the graffiti has a preparation layer or mortar applied to or coating the painted surface, the stacco technique is the most feasible in the removal of paint of a certain thickness. In this case, as with traditional wall paintings, we must protect the painted surface with protective fabrics that adapt perfectly to irregularities, to avoid

unnecessary breakage. Large surfaces cannot be removed in one go with this technique, as the weight and lack of flexibility of the base make removing more than one square metre unrealistic.

The other option, applicable to surfaces which are essentially regular, would be an adaptation of the strappo technique. This requires a minimal layer of sequential paint, has no dimensional limitations and yields good results on surfaces without the use of a preparation layer. This technique can be used to exclusively remove the pictorial film from graffiti, through adhesion.

Since acrylic plastic paint is likely to have been used, the effectiveness of the procedure will depend on the thickness of the paint, the irregularity of the base and the penetration and adhesion of the paint. It is worth noting that removing the pictorial film from graffiti can be very difficult due to the strong adhesion of this plastic paint to the base, and discontinuities can occur in the removal, especially when spray paint is used. Tests carried out on graffiti have given very different results, depending on the aforementioned conditions. For this reason initial removal tests must be undertaken, to ensure their viability. It should also be noted that not all graffiti can be removed and in this case photographic documentation is the only medium to ensure permanence.

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Graffiti can be art, social commentary or vandalism, or all those things. City walls sometimes become real social pamphlets.

Photo: Massimo Virgili (©Unsplash)

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The reality of works of graffiti is that they tend to disappear, not only because of the technique used and the environmental conditions, but also because of the deterioration of the building itself. This graffiti, painted in a house of squatters in Barcelona, now only exists in photographs

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In fact, the real difficulty comes when transferring the removed painting to another base.

Here we see if preparatory work has been done well prior to removal: cleaning, uniform adhesion of the canvas and reversibility of the adhesive. So, a new surface must now be chosen on which to stick the removed painting and the right adhesive must be selected. The work should be placed on a new canvas, which can be synthetic, for this transfer, and subsequently onto a stiffer, inert support. The adhesive used should be as stable and inert as possible, with low acidity, to guarantee long-term durability and reversibility. Indeed, strappo when applied to graffiti must follow the same steps and conditions that we would take into account when applying strappo to a fresco.

Removal of graffiti considered to be vandalism The second issue completely opposite to the previous one, giving rise to a contradiction, is to do with graffiti that is considered vandalism,

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including the typical signatures (tags), messages of love or derision, of social criticism or, simply, pamphleteering. These are not intended to be artistic works, and are usually made with spray paint. This form of graffiti becomes a scourge on society which most urban areas suffer, an activity that is difficult to control, and one which is especially painful to aesthetic sensitivities. The conservation of this type of graffiti is not generally taken into account, so it can be removed without debate, as long as the graffiti (or the space it occupies) does not end up becoming iconic, as has happened with the graffiti and writings on the Berlin Wall.

As long as these inscriptions are located in enclosed buildings and abandoned environments, in remote or hidden urban spaces, as fleeting glimpses along transportation routes, their existence does not present a problem. Therefore, it does not matter whether this graffiti is left to deteriorate over time, out of sight. Nor is the method of removal, when necessary, important, since maintaining the painting or preventing alterations to the base are not factors of any significance.

On the other hand, if graffiti appears on buildings of historical interest, archaeological sites and tourist sites, in shops and homes (which could happen to our own), in new buildings or pub-

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The life of an exposed work of graffiti is short.

Damage to graffiti is visible after a short period of time, as is the case of this mural by Allover at the sports pavilion of Badia del Vallès

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The precariousness of an abandoned building and its location in more hidden urban areas favours the proliferation of graffiti

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Unfortunately, monuments have become the targets of graffiti. This lack of respect for heritage on the part of some creates the perception that graffiti is a dirty and marginalized art, so a distinction must be made between vandalism and street art

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lic spaces, then it must be removed as quickly and efficiently as possible, two conditions which together pose a problem for conservator-restorers. When this happens, especially in visible environments, graffiti cleaning protocols are activated. Each public entity defines and contracts these protocols in their own way. If the graffiti does not directly affect a building protected by law or an archaeological site that requires the approval of the Generalitat, its removal is not usually entrusted to a conservator-restorer. In this case the damage and alteration resulting from an aggressive removal of the graffiti can be even worse than that initially caused by it.

The protocols offered by most industrial cleaning companies for graffiti removal in cities are usually based on agile and aggressive methods, designed specifically for pavements and solid surfaces made from technically compact materials, such as Portland cement and terrazzo. These surfaces are characterized by their hardness and resistance, typical of industrial or road surfaces, and vary greatly from the sensitivity of the surfaces of historical buildings and monuments.

In short, the methodology of these companies is generally straightforward. Regardless of the surface, a pressurized water jet is always used, potentially accompanied by an industrial cleaning product. Needless to say, there are companies that directly blast with some form of aggregate, which essentially removes the graffiti and everything surrounding it. If pressurized water does not work effectively, the most common solution is to reinforce the process with a very simple chemical cleaning system: scrubbing the graffiti’s surface. This consists of applying a very acidic pH soap which can dissolve any type of paint. It is left on the surface for a few minutes

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and then a pressurized water jet is applied to remove the residue and wash the surface until the paint has been removed. Having applied a very acidic solution, for safety and operational guarantee reasons, it must be neutralized with a basic pH product. An alkaline gel is applied to the treated area, in theory neutralizing the acidic residues which remain on the surface. This is left to act for a while and then washed and diluted with pressurized water, leaving the area free of any graffiti. The means the affected material receives a barrage of excessive treatments over a short period of time: the hydrogen power of the cleaning solution, excessive moisture and a great deal of abrasion. If the wall is porous, the water will significantly penetrate the surface, creating a short-term conservation problem. In addition, a polluting waste product has been generated, which will drain into the ground, will not be collected or recycled and will end up harming other materials and living things.

This aggressive cleaning methodology can be similarly applied to any surface, pavement or element of an urban landscape, regardless of location or state of conservation. If the surface is hard, like a cement pylon or the cobbled surface of a square, it does not matter which removal method is used; a jet of pressurized water, a jet of sand, heat, caustic solvents or cryogenic spray, as long as environmental protection and worker health and safety is taken into account.

All of these industrial procedures are dramatically disproportionate and do not adhere to any conservation-restoration criteria, which is why

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Graffiti removal can involve chemical and physical processes or a combination of these, depending on the type of surface involved.

Photo: Aleix Barberà

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Painting historical heritage with graffiti represents an act of vandalism and a significant attack on heritage. Site of the Iberian town of Castell, in Palamós (Baix Empordà), 2018

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more attention needs to be paid to methods of removal for all forms of graffiti. However, particular care should be taken regarding protected buildings, historical monuments and archaeological sites, as the materials in these cases tend to be delicate. Moreover, many of these surfaces may have a sculpted patina or relief, or contain delicate mortars. Inevitably, these areas require the intervention of a conservator-restorer specialized in wall paintings, and not individuals and companies who lack the necessary training or criteria, and whose sole purpose is the removal of the graffiti above all other considerations.

For the direct removal of graffiti from historical monuments and archaeological sites we should take conservation-restoration criteria and methodologies as our reference. There is no one standard solution that will always provide satisfactory results as historical monuments and sites have many specificities and conditioning factors,. A necessary starting point is to guarantee respectful treatment of the construction in its material dimension at all times, and to avoid using aggressive systems that may compromise its stability. In this way, depending on the surface type and the constituent material, as well as the type of paint used, three graffiti removal solutions may be employed: chemical, mechanical or laser removal, or a combination of all three.

In general, a dry mechanical system can be employed manually (with brushes, scalpels and rubbers) or through the controlled microblasting of aggregates, within appropriate parameters and using appropriate equipment. Currently, there is also equipment that be used to blast steam under pressure at high temperature at specific points, causing the paint to dissolve without harming the base (as long as it is not plastic). This is a fairly effective system for the removal of spray-painted graffiti.

Sometimes it is also possible to use laser removal, a very effective system based on

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Depending on the type of stone, only the affected areas must be cleaned and in a very controlled manner.

Photo: Aleix Barberà

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The removal of graffiti on historical monuments is always complex, and must be done by specialist conservatorsrestorers.

Removal of graffiti cleaning with spray cleaner.

Monastery of Sant Cugat del Vallès (Vallès Occidental county), 2018

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sublimation which does not damage the base material and which is also completely environmentally friendly. If the colour of the surface and the graffiti allow for this technique, it is the optimal removal technique, especially on stone, mortar and metal, and complements other cleaning systems very well.

Traditional chemical cleaning is based on the use of pure solvents applied directly to a surface or using swabs (papette, in Italian). They are used to remove the applied paint, which can cause problems during dissolution if the surface is very porous. The most recommended system today is the use of gelled buffer solutions, which keep the solvent under control on the surface, and which are often combined with microblasters and lasers. This technique requires some knowledge of applied chemistry and the use of aqueous gels using the Wolbers methodology, also developed

by Cremonesi and Baglioni. We will not go into detail about the methodology behind aqueous gels, but it should be noted that they are the most effective and least aggressive way to remove graffiti from delicate surfaces, with no impact on the base support or the environment, and are compatible with a green chemistry approach.

Obviously, to prepare the gels there must be an accompanying preliminary study and analysis in order to determine what the support material is, what type of paint has been attached, and the pH values and conductivity of the materials.

The removal and cleaning of graffiti and tags in cities and cultural settings is a necessity that should not treated lightly, from a technical point

of view. As we have explained, there are three recent examples of this kind of work at the Naveta des Tudons, in Menorca, the Iberian site of Palamós Castle and the Romanesque monastery of Les Franqueses, in Balaguer; all three spaces attacked with vandalistic graffiti.

An alternative to help the removal of graffiti is the use of what are known as anti-graffiti products found on the market. These should be used be responsibly with preliminary testing.

These products protect the surface of a wall from potential graffiti, or from the recurrence of a graffiti in one same place, as they prevent the paint from sticking to the surface. Applied directly in liquid form, they create an insulating film that acts as a barrier between the base and the graffiti, preventing it from making direct contact with the wall and facilitating the subsequent removal of the graffiti.

Basically, there are two types of anti-graffiti products: those that are destroyed once graffiti has been removed (temporary) and those that remain to provide a protective base on the wall (permanent). Temporary anti-graffiti products such as acrylic-styrene copolymer solution, with the addition of silicone oils, must then be removed with a mixture of solvents and subsequently washed with water. Permanent anti-graffiti products are polyurethane varnishes, which are high in solvent resistance, with the addition of silicone oils, making it difficult for the graffiti to adhere. In this case the same cleaning method can be used, but without the removal of the protective layer. Medium-lasting silicone,

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are included in corresponding municipal ordinance texts, regarding the visual maintenance of the urban environment, and can end in significant fines and convictions, depending on the severity of the action. In any case, this process ultimately represents a significant expenditure of time and money, in addition to the wear and tear of the damaged surface. Basically, everything starts with the cultural education we receive and our knowledge of the value of the heritage that surrounds us, as something that must be protected and respected.

The task of preserving or removing graffiti from a historic location should be unique and exclusive to conservators-restorers trained in wall paintings, as it requires specific criteria and methodology, applicable to all affected spaces, materials and surfaces, whether ancient or modern. Today, we are all sufficiently well informed to appreciate this.

Graffiti allows the artist to play with both urban and rural architecture.

Penelles, 2016

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synthetic anti-graffiti products are also manufactured, with are highly hydrophobic and lyophobic, preventing the paint from sticking These products may provide a solution for the removal of vandalistic graffiti, but they do not take into account the base, especially when it is made of a sensitive, porous and easily disintegrated material. These products may be suitable for certain supports and new buildings, but should not be used for historic buildings and monuments, sculptures and archaeological sites, due to their low transpiration. In any case, it is always better not to use a film-forming product of this nature and to instead adopt appropriate preventive conservation measures.

Conclusion It is clear that most of the time the removal of graffiti through cleaning tends to be done at some speed, regardless of the building, monument or site where it is located. If the structure has no form of official legal protection, and no specific filter or requirement for removal projects, the consequences of cleaning away graffiti can be disastrous.

We already know that it is difficult to tackle vandalistic graffiti, and that it is a problem for all cities, despite attempts to educate people on this matter. Many of the most common infractions regarding misuse of the urban landscape correspond to vandalistic graffiti. In some cities they

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The large works of graffiti that decorate architecturally simple and mediocre buildings end up embellishing them and become part of the essential urban aesthetic.

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CONSERVACIÓ PREVENTIVA

The first workshop (course/action) in Catalonia

OUR REGION HAS A WIDE NETWORK OF MUSEUMS AND CULTURAL FACILITIES that safeguard a great artistic heritage.

Introduction Of these collections, only a part is on display. This pattern is the same worldwide: according to a study carried out by UNESCO (United Nations Educational, Scientific and Cultural Organization), between 10 and 20% of museum collections are on display, while the rest, 80 or 90% of the total, are in storage areas.

As a general rule, the area set aside for storage usually represents 10% of the total area of the museum, despite containing the largest volume of the collection in terms of quantity, which leads to a high occupancy density in a space that is usually small. Moreover, on many occasions, the storage area, which should be dedicated exclusively to hosting a collection, ends up being a space for storing many other things, so the storing of the collection becomes of secondary importance face in the face of other emergencies and budgetary needs.

In the face of this and other problems linked to storage areas, evidenced by an audit carried out

by UNESCO in 2011, the ICCROM (International Centre for the Study of the Preservation and Restoration of Cultural Property) and UNESCO promoted the Re-Org method, reviewed and updated in collaboration with the CCI (Canadian Conservation Institute).

The method has been successfully applied to 83 museums in 27 countries on 5 continents. This

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Start of the course by Mireia Rosich, director of the Víctor Balaguer Museum Library, in Vilanova i la Geltrú

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All ready for the start

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method can be used to plan and implement a project for reorganizing the storage areas of a museum and is designed to provide step by step guidance in the process of reorganizing the space. It has been designed to be simple and adaptable to all types of collections. The method prioritizes the reuse of existing resources and the importance of teamwork.

The deployment of the Re-Org initiative in Catalonia is done from the Museums Department, under the technical direction of the CRBMC (Centre for the Restoration of Artefacts of Catalonia). This action is part of the preventive conservation strategy provided for in objective 4.5 of the document 2030 Museum Plan of Catalonia, one of the objectives of which is improving the storage areas of our museums.

The Re-Org methodology was proposed and chosen by the CRBMC as the tool that should be applied for this purpose. In order to publicize and implement this method among Catalan museums, in 2019 the Catalan Ministry of Culture signed a collaboration agreement with ICCROM. The CRBMC plans to implement the method through territorial networks, with the support of the Barcelona Provincial Council. Those museums that need it will receive advice and will be accompanied by mentors during the implementation process.

Annual action courses or workshops will he held throughout the territory, which will allow

M. José Gràcia, Coordinator of the Preventive Conservation Department of the CRBMC

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Lesson: "Collection not collection"

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Lesson: “Distribution of space"

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participants to learn about the method in a practical way and apply it to real cases. At the same time, the CRBMC, with the support of the mentors of each network, will offer advice to those museums that want to fully or partially implement the methodology in their reserve collections.

During 2019-2020, the manual was translated into Catalan, in order to facilitate its dissemination, and the first course/action was carried out.

It is worth stressing that this was the first Re-Org workshop held in Catalonia and Spain. The museum chosen to carry out this first course was the Víctor Balaguer Museum Library in Vilanova i la Geltrú.

The Víctor Balaguer Museum Library was founded at the end of the 19th century, to offer the public the opportunity of seeing together in one place several collections of art, books and ethnographical works that Víctor Balaguer had accumulated throughout his life. As a result, it is a very diverse collection, an important factor in organizing a course/action of this nature.

The part of the collection not on display is distributed across three storage areas: two located in a building near the museum, on the

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Working as a team

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other side of the street, where there are also offices which are actually considered the museum's reserves, and a small space in the building called Santa Teresa, located in the garden of the museum, which was the home of Víctor Balaguer. This multipurpose space serves as a warehouse for various materials, a space for educational use and a storage area for the reserve collection.

The issues affecting the storage areas of the Museum Library can be extrapolated to many museums in our territory: problems in accessing the collections, lack of storage space, insufficient furniture, dispersion of the collections, objects left on the floor, mixing up of collection and non-collection items etc.

From the very start, the institution was happy to collaborate and participate in the project. The Víctor Balaguer Museum Library facilities were big enough to accommodate the twenty-one participants, and the variety of the collections allowed the participants to tackle different issues during the implementation of the method.

The aim of this first course, in addition to reorganizing the museum's storage areas, and grouping and improving the accessibility of the collection, was to train the professionals who will then provide support to museum staff in the implementation of the method across Catalonia.

The course, taught during the month of December by Gaël de Guichen, with the support of two local mentors, one from the MNAC (National Art Museum of Catalonia) and one from the CRBMC, was attended by twenty-one professionals from the museums of the different regions, as well as technicians from the ICUB (Barcelona Institute of Culture) and the Network of Local Museums of the Barcelona Provincial Council.

This workshop has been divided in two parts.

The first, as already mentioned, was held in December 2019, and served to carry out phases 1, 2 and 3 of the method. The second part, which

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involves phase 4 or the physical reorganization of the museum's reserves, was scheduled for spring 2020. In the end, due to the pandemic and the declaration of the state of alarm, this was not possible. Phase 4 has been postponed to the last quarter of 2020 or early 2021, depending on how the health emergency develops.

How is the workshop structured and run?

With the experience gained over the years, ICCROM has established 10 quality criteria that any reserve collection needs to meet. Using these 10 criteria as a basis to carry out the reorganization through teamwork and planning, the method is structured around four pillars that encompass all aspects related to the storage area: • Building and spaces • Furniture and small equipment • Management: policies and procedures in relation to the functions and responsibilities of the staff working in storage areas.

• Collections that are preserved The work methodology is structured in four phases, and the participants are organized into working groups, usually made up of four members. Each group is identified by a colour.

Phase 1: Launch A self-assessment is carried out, so the museum can quickly gain an overview of the situation and identify the most significant weaknesses and/or problems. The tools, materials, photos, plans and videos documenting the storage area “before the Re-Org” are gathered together and the action areas are also defined.

The self-assessment involves a simple form that consists of four sections of analysis:

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Session: task organization, Teamwork

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Work sessions (green to agree and red to disagree)

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Management (G), Building and space (E), Collection (C) and Furniture and equipment (M). Each section includes between eight and ten statements/questions describing optimal situations.

The museum/user chooses the option that best reflects their reality. Once completed, the total score obtained in each of the sections must be added up and the corresponding result must be circled in the diagnostic table. During this phase, the team that will participate in the reorganization is trained up. Across ten lessons, participants review concepts and go from being a group to becoming a team, a concept and the driver of the method’s working spirit.

Phase 2: report on the conditions of the reserves During this phase, the state of the storage area or areas is documented and analysed and a concise and credible report is prepared for the management team or those with decision-making powers. This report highlights any key issues affecting the conservation and access to the collections stored there.

Phase 3: Warehouse action plan Based on the above report, the step-by-step reorganization project is planned and submitted to management for approval.

The aim is to make it easier to access the collections through their physical reorganization.

It is worth remembering that making access to collections easier is the first task before any other improvements can be implemented, such as updates to documentation, building renovations, policy and procedure reviews, etc.

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Re-Org official infographic

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Participants in the first Re-Org workshop in Catalonia

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Phase 4: Implementation of the storage area reorganization The action plan is implemented in this phase. This is when objects are physically moved. Up to this stage, the entire study has been carried out without physically handling the objects in the collection. It is crucial that any changes are documented.

This is the moment when the participants put into practice everything they have learned, and when teamwork really proves its worth.

The experience of all the participants in the

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Gaël de Guichen, during a visit to the museum halls

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Re-Org workshop carried out in the Víctor Balaguer Museum Library, despite being exhausting, with very intense and very long working days, was very satisfying and enriching. We hope to be able to carry out the pending phase and plan the following one as soon as possible.

From this point, an in parallel, the CRBMC will work with the territorial networks of museums to implement the Re-Org method and adapt it to the characteristics and needs of the museums in Catalonia.

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CONSERVATION-RESTORATION

CONTEMPORARY ART

Application of the dust peeling technique in a work by Borrell

ALFONS BORRELL I PALAZÓN IS ONE OF THE MOST IMPORTANT CATALAN ABSTRACT PAINTERS. His works are characterized by bright colours and geometric shapes.

Introduction The work in question is a large canvas, a collage of cloth on cloth; on a green and grey background, Borrell places a monochrome red square.

State of conservation The work was in the Palau de la Generalitat and was taken to the CRBMC for an intervention after a leak that caused dirty water to drip onto the pictorial layer.

In addition to photographically documenting the work to keep track of its condition, once in the photographic studio, various photographic techniques were used to more accurately analyse the effects of the water drippage on the work. Photographs were taken of it using raking and ultraviolet (UV) light. Fibre samples were also taken to reveal the composition of the canvas and the technique

used, since in contemporary painting matte monochrome finishes can be achieved with various media that are not necessarily evident at first sight.

Various techniques are too often included under the generic acrylic paint umbrella when they should not be (as happened to us with this work, which was classified as acrylic paint).

Of the tests performed, the information provided by the ultraviolet analysis was particularly revealing. First of all, we noticed that the grey-green background is finished with varnish (even the brushstrokes are visible). By contrast, the red square showed no fluorescence, so we now know that the author left it with no protective top layer (presumably to accentuate the matte texture of the cutout).

The laboratory analyses revealed that the canvas is made of linen fabric, and the results of the Fourier Transform Infrared Spectroscopy (FTIR) showed that the pictorial binder used in the greens is polyvinyl resin (PVA) plus a filler of calcium carbonate (CaCO3), an additive typically used in the formulation of vinyl paints. Meanwhile,

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Work before the intervention

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Painting photographed with UV light before the intervention

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Esther Gual, coordinator of the Contemporary Art Conservation-Restoration Department

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Painting photographed with raking light before the intervention

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Close-up of the use of agarose discs.

Photo: Teresa Schreibweis

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the red is also bound with PVA and, in addition to containing calcium carbonate, also contains barium sulphate (BaSO4), which is often been used as an artificial mineral pigment to lower the costs of other more expensive white pigments, but also functions as a filler in pictorial preparations. This information from the laboratory was essential prior to the cleaning of the pictorial layer, since vinyl paints are usually very sensitive to aqueous media (swelling, leaching, migration, activation of surfactants, etc.) and many solvents.

Intervention To design a suitable cleaning method, it was necessary to first know the pH parameters and the conductivity of the pictorial layer. Before measuring these, we removed the surface dust with a very soft brush, so that the dirt would distort the results of the tests we would carry out with pure agarose gels (A9539 Sigma-Aldrich®).

Measurements were taken at thirteen representative points of the work that included all the colours. The range of the result of the measurements of the pH oscillated between 4.9 to 7 in the varnished grey-green background, and were much more acidic in the red box (unvarnished) between 2.6 and 4.2. In terms of conductivity, we found a range of 80 to 123 µS/cm in the red fabric and 79 to 180 µS/cm in the background colours.

Once we had characterized the surface we wanted to treat, we had to determine the type of cleaning we wanted to carry out: did we want to clean by preserving or by removing? The answer seemed clear: we wanted to remove the dirty water stains, but without this entailing an overall cleaning of the work. This premise had to be kept in mind when designing the methodology and products to be used.

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Linen fibre at 200x magnification

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Front of the green paint sample at 50x magnification

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Given that we were dealing with a pictorial layer that was very sensitive to chemical cleaning, we decided to start with a dry clean. We first tried a series of rubber erasers: in powder (STEM), Staedtler® eraser and Maimeri® 6255000 eraser, which did not clean the drips and also left residue in the interstices of the fabric.

Since the result was not satisfactory, we then tried a vulcanized natural rubber sponge (known as "smoke sponge"), a soft white Akapad® and makeup sponges made from polyurethane esters, because these have been extensively tested, are neutral and leave no residue. The results, however, were disappointing, because they also failed to remove the dirt from the drips.

Equally unsuccessful were the tests carried out using microfibre dishcloths. We then decided to test an aqueous system adapted to the conditions (pH and conductivity) of the surface we wanted to

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Cleaning tests using different tapes.

Photo: Teresa Schreibweis

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treat. In terms of pH, the cleaning solution could not be ionizing, as this would increase the hydrophilic character of the pictorial surface and cause swelling and bleaching. This meant that it had to be equal to the pH of the area we wanted to treat, but within a safety margin, which could not fall below a pH of 5.5. The problem we encountered, however, was that in the area of the red piece of fabric, the pH of the surface ranged from 2.6 to 4.2. Therefore, we could not adjust the solution to these parameters, as it would not be safe, and if we used an ionized solution, this might produce harmful long-term effects. In terms of the background of the piece, since the pH range was between 4.9 and 7, we decided to create three buffer solutions with a pH of 5.5, 6 and 7. In general, these solutions cleaned very little and with a pH of 7 they washed away the colour, even though the moisture was removed with a vacuum cleaner while the aqueous solution was being brushed on.

Therefore, we tested the use of buffer solutions with chelating agents, specifically a buffer solution with a pH 5.5 of containing citric acid, which acts as a buffer and weak chelating agent, and another with a pH of 6.6 and DTA which acts as a strong chelating agent. The solutions were also gelled with 4% Klucel® and 3% Vanzan® NF-C. The result was not good either, and what concerned us most was that rings were forming around the treated areas.

We have already mentioned that the red area could be treated with chemical agents due to the pH of the paint. The application of cyclomethicone D5 did not even manage to temporarily waterproof the pictorial surface, since the red area has no preparation layer and the silicone was absorbed and did not remain on the surface; therefore, it did not perform its function as a barrier.

Discarding wet methods altogether, we decided that the only solution was to design a more effective dry cleaning system than those used so

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Removing the dirt.

Photo: Teresa Schreibweis

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Close-up of the effects of drippage, before the restoration.

Photo: Teresa Schreibweis

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far. We devised a system to remove the dirt, by applying adhesive tape directly on the dirt drip, and once the contact was secure, the tape was gently removed. The dirt did indeed stick to the adhesive part of the tape. To find the right product, we tested with various tapes used in paper conservation-restoration and observed the results with a binocular microscope; in other words, we looked at the tape with a magnifying glass once it had been removed, to check that we had not stripped away any paint particles, in addition to the dirt. We also checked with UV light that there was no adhesive residue left on the pictorial layer.

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After several tests (to check whether the tape adhesive was neither too strong nor too weak and left no residue), we decided on the Neschen Filmoplast® P 90 tape, stable, durable and flexible, with a 2 cm wide neutral acrylic adhesive. The tape was stuck to each drop and removed three times, having noticed that if we did it more insistently the adhesive was left with traces of pigment. After three goes, we would stop.

Although we achieved a good degree of cleanliness, we were not able to completely remove the drips, but we decided that this was the safety margin in which we wanted to move and we stopped the intervention at this point. The work was then retouched with pure pigment, which was

bound with alcohol so it could be picked up by the brush, but which was applied dry on the work (the alcohol evaporates quickly) especially in the red area, which was the most affected. This method of reintegration was very subtle, but since the work does not support any type of wet environment, it was a reintegration that did not cause stains or rings, since the pigment was suspended in dust on the surface.

Finally, a protective layer was applied to the back of the work with Tyvek® to protect it from microparticles and to mitigate possible humidity and temperature variations that it might suffer in the future. The Tyvek® was attached to the perimeter of the frame with an adhesive strip one centimetre wide.

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Painting after the intervention

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DETAILS GENERIC CLASSIFICATION: contemporary art | OBJECT: painting | MATERIAL/TECHNIQUE: painting on canvas. Vynil and collage on canvas | TITLE/TOPIC: 4-9-89 | AUTHOR: Alfons Borrell (Barcelona, 1931 - Sabadell, 2020) | DATE/PERIOD: 1989 DIMENSIONS: 170 × 195 cm | ORIGIN: Palau de la Generalitat, Barcelona (Barcelonès county) | CRBMC REGISTER NO: 13583 | INVENTORY NO: 228147 from the art collection of the Government of Catalonia | COORDINATION: Esther Gual and Maite Toneu | INTERVENTION: Esther Gual, Ione Iturria, Teresa Schreibweis and Maite Toneu | YEAR OF RESTORATION: 2019

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Centre de Restauració de Béns Mobles de Catalunya

INNOVATION AND RESEARCH

PAINTING ON WOOD

Altarpiece of Santa Maria de Palau-Solità

THE PAINTING IS ATTRIBUTED IN PART TO THE MASTER OF ARTÉS, the name given to an anonymous painter from the Valencian school from the circle of the master of the Perea.

Introduction Despite its uneven style, since it is the work of different artists, the panels were painted around the same and the street scenes are coherent in their iconography. The four panels attributed to the master are: The Adoration of the Shepherds, The Adoration of the Kings or The Epiphany, The Ascension and Pentecost. The set also contains, made by a different hand, the scenes of the Annunciation, the Resurrection and Calvary. The predella contains two scenes of the Passion: the Kiss of Judas, the Road to Calvary and also Christ in a tabernacle. The piece is completed with a depiction of Saint Peter and Saint Paul on the doors of the altarpiece.

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Close-up of the Epiphany scene attributed to the Master of Artés

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Today, the altarpiece includes a series of modern elements and the odd mutilated area which led us to search for the historical and documentary information that would provide answers as to what happened to it over the years.

The people of the village who knew the altarpiece’s most recent history told us that, during the Spanish Civil War, residents of Palau dismantled it and hid it so that it would not be destroyed.

Joaquim Folch i Torres, as head of the Catalan Government’s Artistic Heritage Commission, managed to save it: the altarpiece was first taken to Olot and then to Paris, away from any war zones. After the war, in 1940, the altarpiece returned to the parish, was erected in the chapel of the Rosary and was not re-installed on the high altar until the 1960s.

Some photographs from the Mas Photographic Archive at the Amatller Institute provided some interesting information, allowing us to confirm that between 1960 and 1962 it was dismantled from the chapel of the Rosary and restored and reassembled on the high altar of the church. The comparison between the 1960 photograph and the current one provided a great deal of information about the state of conservation of the altarpiece and all the elements that were added and removed, once the restoration was completed. The most visible added modern elements were: the entire upper crowning, the central one (above the niche) and also the one above the door of Saint Peter.

The restoration that took place in the 1960s followed the criteria of the time, involving a very invasive action. The scenes today reveal that excessive pictorial reintegration was carried out that masks the original work a little.

Curative conservation intervention and study of the work The intervention proposed for this altarpiece involved taking corrective action through a curative conservation process, in situ, which focused mainly on the polychrome, and, while also carrying out a complete study of the work with the help of the technicians and scientists of the CRBMC.

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KREIT-restauro, SL, art and heritage conservation-restoration

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The altarpiece before restoration

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The aim of this study was to acquire more information about the technique used to create the work and to understand the nature and composition of its materials, as well as to carry out an organoleptic examination that would provide a better understanding of the state of conservation of the work and its pathology.

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Organoleptic examination and state of conservation The altarpiece is currently mounted on a new pinewood structure, and the work as a whole is fastened to the stone wall at the back of the presbytery with iron anchors. There is practically no separation between the altarpiece and the wall so the back cannot be seen. This makes it hard to carry out a proper structural analysis and also to

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Photograph of the altarpiece from 1921. Photography: © Photographic archive of the Centre Excursionista de Catalunya (AFCEC) Genovart X (1858)

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Photograph of the altarpiece from 1960. Photography: © 2017 Institut Amatller d’Art Hispànic im.05435012 (photo Gudiol 42516 1960)

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perform the appropriate checks on the state of conservation of the wood.

The base material is white poplar wood. There is significant structural deterioration, probably because it has been subjected to unfavourable environmental conditions, resulting in an attack by xylophagous insects, and also because of the adverse vicissitudes it has experienced (various disassemblies and assemblies) as described in the introduction. The attack, still active, has caused an internal weakening of the wood and given it a frail texture, especially in the elements of the canopy. This pathology has been mitigated by sticking some plywood sheets to the back The long pinnacles separating the scenes are replacements of the originals that were nailed to the painted panels of the altarpiece. Today we can

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still see the holes from when they were removed (during the altarpiece’s disassembly). The new ones have been fastened with many nails and screws.

As for the polychrome of the scenes, the cohesion and adhesion of the pictorial layer of the tables is good. There are significant losses of polychrome on the bottom of the panels of Saint Peter and Saint Paul, in the area where they were slashed –more or less in half– at some point in the altarpiece’s history.A lot of losses can also be observed in the gilded canopy and pinnacles, which have been repainted with purpurin –in many places, directly on the wood.

What really stands out upon initial observation of the polychrome is its good state of conservation, despite the passage of time and its historical

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vicissitudes. A closer look at the scenes shows that all the panels have been heavily reintegrated, and that many of these reintegrations probably cover the original paint.

As for the surface layer, a visual examination also reveals the existence of one or more varnishes applied to the entire surface of the work. In addition to surface dust, there is a lot of dirt attached to the paint, located mainly on the upper panels.

Intervention The curative intervention of the altarpiece consisted of a mechanically cleaning of the surface dust, and also the disinfestation of the wood in the parts that were accessible. The polychrome and gilding were affixed with Lefranc & Bourgeois® leather glue in a ratio of 1:13. The application of putty to the losses of the pictorial layer of the panels of Saint Peter and Saint Paul was carried out in the usual way with leather glue and white glue, having first carried out a reintegration with the idea of creating an illusion, first

Photograph in ordinary light of the face of Saint Paul

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Uplifted and missing parts of the polychrome on the door of Saint Paul

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Photograph ultraviolet (UV) ordinary light of the face of Saint Paul Photography: Kreit-restauro, SL

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Window for cleaning tests. Photo: Kreitrestauro, SL

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Adherence of the polychrome on the panel of Saint Paul.

Photo: Kreitrestauro, SL

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Visual examination of the altarpiece scenes. Photo: Kreit- restauro, SL

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with watercolours and then with pigments bound with Laropal® varnish.

As well as conservators-restorers, photographic and chemical technicians from the CRBMC were also involved in carrying out the analysis of the altarpiece. Photographs were taken with general and detailed diffused light, as well as infrared (IR) and ultraviolet (UV). The examination of whole altarpiece using ultraviolet and raking light confirmed the large number of retouched parts, some sticking out prominently, which cover cracks, scratches and large missing parts. Using infrared light, the losses were perfectly outlined and it showed the areas where the touch ups invade the original polychrome. Under ultraviolet light, a bluish layer appeared to cover the whole of the altarpiece, with the exception of the lower parts of the panels of Saint Peter and Saint Paul.

The analysis revealed the existence of different varnishes: a rosin varnish in an older layer and a more recent ketone one. This resin, now yellowed, forms a surface film that helps to hide existing alterations and, at the same time, distorts and masks the original tones of the work. The fact that the ketone varnish layer does not appear in certain reintegrations confirms that these are older.

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Stratigraphy of varnishes under ultraviolet light. Photo: Ricardo Suárez (CRBMC).

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execution between the four panels attributed to the master of Artés and the others whose authorship is unknown.

Surface layer: the analysis revealed that all the panels a surface layer comprised of a semi-transparent ketone synthetic resin (bluish fluorescence), probably applied during the intervention that took place between in 1960-1962. In some analyses, this resin was found with strips of beeswax, which could be from an earlier or later intervention or even a constituent part of the resin, to make it more matte. Meanwhile, in the windows created for cleaning, we found several areas with traces of natural resin, supposedly rosin (green fluorescence).

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An organoleptic examination was carried out, During the analysis using ultraviolet followed by a detailed mapping of the state of (UV) light. Photo: conservation, in which the pathology detected Kreit-restauro, SL

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was indicated.

The sampling enabled us to analyse and determine the artistic technique used, and the nature of the base material and the surface layer: Base material: The analysed wood of the panels that could be accessed was from the Populus alba family. Several samples were analysed in three different areas of the altarpiece.

Pictorial technique: samples were taken from all the panels to make a comparison of the technique and the materials used, and to analyse whether there is any notable difference in

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The main technique used in all the panels is oil, although we cannot rule out that some of the pigment may be bound with a protein substance.

The preparation is made of gypsum and animal glue, and in some of the samples taken (both from the work of the master of Arts and the others) there is a layer of white lead bound with oil on top of the layer of gypsum and glue. We also found that, in the two lower panels — those of Saint Peter and Saint Paul — the preparation layer is brown.

As for the pigments used, they are also the same across all the panels. The blues are azurite, the greens are verdigris and there is also red shellac, vermillion, bone char and lead-tin-yellow, known by the Italian name of giallorino, widely used between the 15th and 16th centuries. The skin tones are made with white lead mixed with other pigments such as azurite.

The results of the analysis in the blue of the canopy indicate the presence of two blues: the upper blue layer is composed of ultramarine blue and a protein glue, and the lower blue layer is azurite blue.

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Mapping of structural elements. Design and photo: Kreit-restauro, SL

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Nails / spikes Rivets Screws / lugs Burlap Rivets underneath the polychrome

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Mapping of new elements and losses in the base material.

Design and photo: Kreit-restauro, SL

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New non-original elements Loss of base material Board joints

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1

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Close-up of the trim of the robe of Saint Peter containing mordant gilding

2

4

3

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5

Polychrome

1

Blue

Ultramarine blue, protein binder

Resin

2

Yellow

Not analysed

Polychrome

3

Blue

Azurite

Bole

4

Brown

Red bole

Preparation

5

White

Gypsum

In all the panels we observed a huge variety of different techniques of application and decoration of the gilding: water gilding, mordant gilding, chiselling, estofado, mecca gilding, shellacs and the application of a painted decoration of the gown of the Virgin Mary, with a little relief, in a dark colour.

The sample taken from the golden trim on the red cloak of the door with the depiction of Saint Peter explains the technique of execution: it is a mordant gilding, a mixed gilding system also known as assist gilding in which the painter painted the trim of the gown using a resin or mixture on the red paint of the saint's cloak and at the right stage of stickiness added the gold leaf that adhered only to those parts where the mixture had been applied. Meanwhile, the results of the analysis of the dark decoration in relief of the dresses of the Virgin Mary indicate that the layer of dark polychrome contains the pigment azurite with a filler of gypsum, carbonate and glue, and is applied using on the water gilding.

The surface cleaning and varnish removal tests helped us establish the protocol to bed followed in a future second phase of intervention.

The tests were carried out on the panels of the Crucifixion, the Annunciation, the Epiphany, on the panel of Saint Peter, on the panel of the Kiss of Judas and on the Virgin Mary of the Tabernacle.

Cleaning tests performed on polychromed panels:

1

2

3

4 5

Gilding

1

Yellow

Làmina d’or

Resin

2

Yellow

Resin

Polychrome

3

Pink

Shellac, aluminosilicate (Fe2O3), white lead

Policromia

4

White

White lead

Preparation

5

White

Gypsum

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1. Aqueous surface cleaning with regulated pH: the aqueous test of the CRBMC cleaning protocol was performed in order to determine the most suitable buffer solution to remove the adhered dirt. We chose a pH 7 buffer solution with a weak citric acid chelating agent as the most effective.

This method cleans while preserving the ketone varnish applied in the restoration of the 1960s and also the numerous retouches.

2. Cleaning with solvents: we performed the solvent solubility tests, (in accordance with the solubility test proposed by Cremonesi, tried and tested by the CRBMC):

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Example of decoration with dark-coloured relief

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• IE (isoctane + ethanol): in different proportions, from an IE3 to an IE5. This mixture of solvents reduced the ketone varnish layer (which is slightly altered and turns yellow) while leaving the retouches in place. This allows a controlled removal that respects both the interior varnish and the retouched and repainted parts, and allows us to select which ones to remove or keep.

• Richard Wolbers IE3 non polar gel solvent: using a gel solvent controls the time it is allowed to act and reduces the risk of penetration and evaporation of the solvents contained in the gel.

We left the gel on the surface for three minutes.

The result was an effective removal of all the ketone varnish. It also removed the touch-ups carried out in the previous restoration. It was difficult to remove all the gel, which required repeated rinsing with a mixture of non polar solvents.

• Emulsion of the solvent gel IE3 with a buffer solution (pH 7): the final result is similar to the previous one. Perhaps it was a little easier to remove the emulsified gel and rinsing was not required. The end result was the complete removal of the ketone varnish and also the touch-ups.

3. Specific gilding cleaning tests: • W/O fatty emulsion: this combines the solvent power of water with a non polar liquid. It was very effective in cleaning the gilding, because the water inside the micelle of the surfactant is never completely free on the surface. The result of the gilding cleaning tests was satisfactory.

In conclusion, the examination and the scientific-technical study of the altarpiece will help us to define an intervention approach that is based on a deep knowledge of the work, and which we will have to carry out and develop in a future second phase of restoration.

DETAILS GENERIC CLASSIFICATION: painting on wood | OBJECT: altarpiece | MATERIAL/TECHNIQUE: polychromed and gilded wood | DESCRIPCIÓ: altarpiece of Santa Maria | AUTHOR: attributed to the Master of Artés. There is evidence that the altarpiece is also the work of two other authors in the same style, but their identity is unknown | DATE/PERIOD: lThe altarpiece was commissioned in 1513 and completed in 1519 | DIMENSIONS: 6 × 3,82 × 0,30 m | LOCATION: church of Santa Maria, Palau-solità and Plegamans (Vallès Occidental county) | CRBMC REGISTER NO.: 13882 | COORDINATION: Pep Paret | RESTORATION: KREITrestauro SL | YEAR OF RESTORATION: 2019

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Centre de Restauració de Béns Mobles de Catalunya

INNOVATION AND RESEARCH

SCULPTURE AND PAINTING ON WOOD

Altarpiece of the Corpus of Girona Cathedral

AT THE END OF 2019, THE FIRST PHASE OF THE INTERVENTION OF THE ALTARPIECE OF THE CORPUS CHRISTI of Girona Cathedral was completed.

Introduction The intervention had two very clear objectives: the first was based on a curative and preventive conservation action for entire altarpiece, as well as the chapel and the two paintings on canvas that decorate the respective walls, while the second was to carry out a historical-scientific study of the altarpiece in order to gain a better understanding of it.

The second phase, following a methodology that will be based on the results obtained in the first, and which has not yet been carried out, will be the restoration itself: cleaning understood as the removal of surface layers and final presentation.

The conservation intervention The conservation work carried out during the first phase consisted of removing as much possible of the external elements of deterioration, curbing the intrinsic alterations of the materials and placing preventive barriers to prevent the reappearance of any of the alteration factors.

The surface dust covering the walls of the chapel and its contents was removed, the flaking of the wall was fixed and the structure of the altarpiece was reinforced, by strengthening the weakened wood and affixing the elements which were in danger of falling. The broken pieces were also reattached and the top of the altarpiece was stabilized with an inert anodized aluminium crossbar attached to the wall.

In addition, other non-structural tasks were carried out, which were just as important, to stop or slow down the deterioration of the polychrome of both the altarpiece and the paintings. To achieve this, the pictorial layer, the gilding and the preparation layer that were coming loose were affixed and a treatment was applied to stabilize the metal elements. Finally, the wood was disinfested and protected on the back.

The preventive tasks included the application of a barrier fabric (Tyvek®) in the horizontal areas

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of the back, so that particles are not deposited directly on the base material. This will prevent the accumulation of large deposits of dust which could retain a lot of moisture.

We would also like to point out that the installation of the scaffolding, both on the front and back enabled us to discover, disassemble and study a stained glass window dating from the 13th and

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General view of the altarpiece before restoration

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Laia Roca i Idoia Tantull, conservator-restorers of sculpture and painting on wood

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During the process of affixing the pictorial layer. Photo: Idoia Tantull

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Protection of a horizontal area on the back with barrier fabric.

Photo: Laia Roca

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14th centuries, which had been hidden behind the altarpiece since its construction and which no one knew existed.

The scientific-technical study carried out during this first phase made it possible gain a better understanding of certain details of the execution of the work and the materials used in its construction. This study was carried out based on two types of examination: the first based on the observation of the scenes using electromagnetic radiation and the second involving the physicochemical analysis of the materials.

In the first examination, infrared (IR) photography was used, thanks to which it was possible to observe in detail the underlying preparatory drawings of the polychrome panels and even small corrections in the hands and arms. The other observation technique used was ultraviolet (UV) light, which allowed us to identify possible repaintings.

To be able to interpret the results of these techniques, chemical analyses were needed. For example, using both direct observation and observing fluorescence under ultraviolet light, some areas of the scenes were detected as being especially dark with respect to the rest of the polychrome. These parts contain verdigris, a pigment that has the particularity of inhibiting the luminescent response of the binder under UV radiation. Based on these analyses, it was possible to ascertain the presence of this pigment and, moreover, to discover that, in fact, there are three different layers in these areas.

Immediately on top of the preparation layer, there is a layer that contains both white lead and verdigris pigments, bound using oil. On top of this, there is a second layer made from a resinous substance, and finally there is a third polychrome, the topmost layer, which also contains verdigris pigment, but this time bound using a protein substance. This last layer is probably a glaze applied by the author himself.

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Photographs using infrared (IR) spectrography showing the preparatory drawing and small corrections

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Photographs using ultraviolet (UV) light showing areas possibly repainted with verdigris pigment

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Graphic report showing the areas where there are decorations with silver leaf. Design and photo: Laia Roca and Idoia Tantull

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The second type of examination used various analysis techniques, including stratigraphic observation and photography through an optical microscope (OM), and the analysis of samples using Fourier Transform Infrared Spectroscopy (FTIR) and electron microscopy with energy-dispersive Xray detector (SEM/EDS). These revealed the nature of various pigments (azurite blue, lead-tin-yellow, white lead, red shellac, etc.) and the presence of two types of varnishes on top of the polychrome: a varnish or surface layer containing proteins and aluminosilicates, spread all over the scenes, giving them a darkened appearance, and an alkyd resin detected here and there. In some cases, it was also possible to determine the type of binding medium, such as oil in the scenes.

The analyses of the base wood and the pictorial technique of the altarpiece revealed that the niche of the upper level was not a later addition, as it might appear due to the simplicity of its shape, but was part of the original piece built by the master Antoni Coll. The architectural elements of the attic are made of Populus alba (white poplar) wood, which matches the materials used in the rest of the piece with the exception of the imagery, for which Cupressus or Cedrus (cypress or cedar) wood was used. But there is another factor that allowed us to confirm that the pieces at the top are original: the identification of an alteration in the silver ornamentation present in various areas of the altarpiece: in the niche of the attic, in the niches of the central level and at the bottom of the busts of the two prophets. In all cases, the alteration is identical, and has been caused by the nature of the materials, the interaction between them, and the environmental conditions. The ornamentation is silver leaf attached to the polychrome with a protein substance. The adhesive had deteriorated which had led to the loss of a significant part of the metal and the underlying polychrome, exposing the preparation layer. In addition, due to the fact that it had not been protected with any varnish, the little silver that was still preserved was blackened, since it had turned into silver chloride due to its contact with the sulphides and chlorides in the air and the glue.

These preliminary analyses focused especially on the shellac pigments of the altarpiece. The sculpted parts and the paintings on the panels

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Close-up of one of the silver leaf decorations of background of the niches, currently very deteriorated. Photo: Idoia Tantull

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Red shellac Aluminium oxide Phosphorus

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Close-up of the clothes of one of the subjects. The only losses are where there is a thick layer of red shellac. Photo: Laia Roca

Basic EDX spectrum of red shellac and aluminium oxide in which the presence of phosphorus (P) was detected

were analysed, and in both cases they contained red shellac. The red shellac that decorates the wings of an angel's head reached us in an optimal state of conservation and the analyses revealed that it contains aluminium oxide (crystalline filler of aluminium oxide, which was applied to give the shellac some volume) and is applied on gold leaf. Based on the results, the binding medium was probably egg, since the spectrum revealed the presence of phosphorous. As for the shellacs bound using oil, that is, those found in some of the clothing in the scenes, these were in a very poor state of conservation. This only confirms the fragility of this pigment, since where it is thicker (shadows of the folds of the dresses) the losses were more than 50%. This is because, since it is not a sufficiently opaque pigment, if it is applied as a paste, it takes longer to dry and therefore cracks, which causes the polychrome to come loose. The analyses also showed that this shellac was applied on top of a layer of azurite and white lead.

As part of the study, in compliance with the CRBMC cleaning protocol, pH and conductivity analyses were also carried out on the different pictorial surfaces using agarose tablets. These

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Conductivity analysis Distilled water

50-55 µS/cm

Agarosae at 4%

70-80 µS/cm

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pH analysis Distilled water

6.0 - 6.2

Agarosae at 4%

6.6 - 6.2

Results of the pH and conductivity analyses.

Design: Laia Roca

— µS/cm

DESCRIPTION

CONDUCTIVITY

NO.

pH

µS/cm

pH

AVERAGE TECHNIQUE

COLOUR

DUST

VARNISH

ZONE 1

ZONE 2

AVERAGE ZONE 1

ZONE 2

1

Gilding

No

Yes

270

500

385

6.6

6.4

6.5

2

Gilding

Yes

Yes

600

-

600

7.0

6.8

6.9

3

Oil painting

Dark

No

Yes

230

220

225

6.4

6.5

6.45

4

Oil painting

Green

No

Yes

350

-

350

6.1

-

6.1

5

Oil painting

Dark

Yes

Yes

270

250

260

6.5

6.3

6.4

6

Oil painting

Light

No

Yes

180

190

185

6.6

6.6

6.6

7

Oil painting

Verd

No

No

156

152

154

6.5

6.8

6.65

8

Tempera

Blue

No

Yes

330

340

335

6.9

6.7

6.8

9

Tempera

Blue

Yes

Yes

520

370

445

6.6

7.1

6.85

10

Skin tones

No

Yes

460

380

420

6.1

6.7

6.4

established the safety margin to be applied to the aqueous products used in the cleaning, so as not to damage the pictorial and preparation layers.

Despite variability of the results, an overall solution was chosen for the whole altarpiece, since it was possible to determine valid safety parameters for the different techniques and surfaces. Fixed values of 300 µS/cm for conductivity and a pH of between 6 and 6.5 (equally safe pH for temperas and oils) were chosen.

After this, cleaning tests were carried out both for dry mechanical cleaning and for the use of solvents in those areas where there were varnishes and repaintings that required removal.

For removing the protein-based surface layer, the most effective solvent was found to be ethyl alcohol. For this reason, aside from the tests using different solvents, cleaning tests were carried out with various solutions and emulsions containing ethyl alcohol. Pure alcohol was suitable for

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the paintings of the panels, but for the sculpted areas the use of polar gel solutions was necessary.

Meanwhile, some repainted tempera areas could be removed mechanically using a rubber eraser and the gilding that did not have a layer of varnish could be cleaned using emulsions, as long as they respected the safety parameters and the results from the analyses. It should be noted that when the cleaning and removal of varnishes and repaintings phase begins, all the colours and techniques of the work must be observed using a microscope to determine if the surface of the work is being damaged.

In conclusion, it is worth highlighting that the study has enabled us to study the behaviour of the materials applied to the work, but that also, based on this, new questions have emerged that cannot be answered in this first phase and which must be further analysed in the next intervention.

Nevertheless, we have now carried out significant

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During the conductivity and pH analyses using agarose tablets.

Photo: Laia Roca

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Cleaning test performed on one of the polychrome panels.

Photo: Laia Roca

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research and gained a lot of knowledge about the work which will allow us to carry out further action with all the necessary guarantees. An example of this is the areas detected with verdigris pigment mentioned above, since special care must be taken in these parts. In any case, it will be necessary to examine other areas of the piece that show similar behaviour through tests, stratigraphical analyses and examinations, in order to be able to assess the need to maintain or remove these layers.

DETAILS GENERIC CLASSIFICATION: sculpture and painting on wood | OBJECT: altarpiece and chapel | MATERIAL/TECHNIQUE: poplar wood, gilded and polychromed in tempera and oil (skin tones and panels) and cypress or cedar wood for the sculptures in the round | TITLE/TOPIC: altarpiece of the Corpus Christi | DATE/PERIOD: 1562-1570 | DIMENSIONS: 8,95 × 5,5 × 1 m | LOCATION: chapel of Corpus Christi, Cathedral of Santa Maria, Girona (Gironès county) | CRBMC REGISTER NO.: 13794 | COORDINACIÓ: Pep Paret | RESTAURACIÓ: Laia Roca and Idoia Tantull, with the collaboration of Judit Birosta for the surface cleaning of the walls and the altarpiece | YEAR OF RESTORATION: 2019

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TRAINING AND KNOWLEDGE TRANSFER

Presentation of CRBMC projects at the conferences of Porto and Pontevedra The studies carried out by the CRBMC of the Roman paintings at Els Munts and the proposed working methodology for the removal of Paraloid® resin, based on a polymer emulsion without surfactants with only 10% solvents, is a topic that had previously been presented at two other international conferences. It was a topic that first appeared at the 5th British Museum Mellon Symposia (a review of which can be found in issue 35 of Rescat).

It was later discussed in a paper selected for the 3rd Green Conservation of Cultural Heritage, organized by the Universidade Católica Portuguesa, in Porto. The forum took place in Porto between 10 and 12 October 2019 and was attended by professionals from all over the world: Norway, Italy, Portugal and Spain, among others. The talk “The removal of Paraloid® coatings with aqueous based formulations. Practical case in frescoes from els Munts roman villa (Catalonia)” was given by Pere Rovira, Aleix Barbe à-Giné and Silvia Marín. The next issue of the Rescat newsletter will include an article dedicated to the studies carried out in els Munts and the results obtained. https://artes.porto.ucp.pt/en/greenconservation2019?msite=9

Meanwhile, on 13, 14 and 15 November of that same year, 2019, the 9th Conservation and Restoration Conference took place, organized by the Museum of Pontevedra and the School of Conservation and Restoration of Cultural Heritage of Galicia, and coordinated by the museum's restorer, Óscar Taboada. That year the theme of the conference was the conservation and restoration of wall paintings, and the CRBMC, through Pere Rovira, collaborated in designing the programme. It took place in the Auditorium of the Museum of Pontevedra, with a capacity of up to 240 attendees, and in addition, all the conferences were broadcast live via the Internet.

The conference was attended by professionals from various institutions. Pedro Echeverría, from the University of the Basque Country, gave the inaugural talk, entitled "The art of brushing and painting churches in the 16th century and the trend of petrophilia in the 20th century."

Juan Manuel Madariaga Mota, from the same university, presented the analytical studies of the frescoes in Pompeii carried out by his department.

There was a representative of the Polytechnic University of Valencia, Pilar Roig, who explained the paradigmatic intervention in the wall paintings of the church of Sant Nicolau de Bari and Sant Pere Màrtir, in Valencia; and Pilar Bosch, who gave a presentation on the possibilities of conservation-restoration treatments using bacteria. Also

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Presentation at the Porto Conference

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Poster of the 9th Conservation and Restoration Conference in Pontevedra

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from Valencia, Livio Ferrazza, a collaborator at the Valencian Institute of Conservation, Restoration and Research, presented the methodology for evaluating consolidation treatments for the wall paintings of Ariadne’s house in Pompeii.

International speakers included Philip Kron, who gave a presentation on the use of the funori seaweed as a product for the consolidation of wall paintings; Lucía Pereira, who gave a talk on the use of the Er:YAG laser for cleaning murals, through a case study from the British Museum; and Simona Sajeva, who spoke about engineering and interdisciplinarity in the sector.

At the Galician level, the conference was attended by professionals from the private sector, such as Celia Casás and Yolanda Gómez, who presented cases of intervention in Galician wall paintings.

From Catalonia, Pere Rovira, of the CRBMC, gave the presentation "Alteration and conservation of mural paintings in situ". The results of a study carried out by the CRBMC on Roman wall paintings in Els Munts and the methodological approach to the aqueous cleaning of inorganic material,

by Aleix Barberà-Giné, were also presented. Mireia Mestre also took part, explaining the conservation of the wall paintings of the National Art Museum of Catalonia (MNAC).

Aleix Barberà, conservator-restorer of cultural artefacts

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TRAINING AND KNOWLEDGE TRANSFER

Series of online lectures on the conservation-restoration of documents, graphic works and photography at the CRBMC Due to the state of alarm and the lockdown that prevented any face-to-face training from being imparted, a series of lectures was broadcast online on conservation-restoration interventions that have been carried out at the Centre for the Restoration of Artefacts of Catalonia (CRBMC), considered of interest to specialists in the subject.

With the collaboration of the Catalan Government’s Centre for Telecommunications and Information Technology (CTTI) and the Catalan Cultural Heritage Agency, and through the YouTube channel Patrimoni.gencat, the CRBMC resumed its knowledge transfer activity with a series of three lectures on recent interventions in the Documents, Graphic Works and Photography Department of the CRBMC, with the following programme:

LECTURE 1: “Conservation-restoration intervention of the graphic work of Caterina Albert (known by her pseudonym, Víctor Català)”

By Carme Balliu. Head of the Documents, Graphic Works and Photography Department at the CRBMC. Live broadcast on Friday 5 June, from 11 am to 12 noon, on the Patrimoni.gencat YouTube channel: https://youtu.be/ xj8Eo8rmY88 LECTURE 2: “Conservation-restoration intervention of the vue d’optique ‘Masked Ball at the Liceu’”

By Berta Blasi. Conservator-restorer of documentary, graphic and photographic heritage.

Live broadcast on Wednesday 10 June, from 11 am to 12 noon, on the Patrimoni.gencat YouTube channel: https:// youtu.be/P8oGc7WVUkY LECTURE 3: «Intervention of the ‘Book for master carpenter apprentices started in 1778’”

By Bárbara Viana. Conservator-restorer of documentary, graphic and photographic heritage.

Live broadcast on Friday 12 June, from 11 am to 12 noon, on the Patrimoni.gencat YouTube channel: https://youtu.be/ V2dHMWkRVr4

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Image of two of the slides

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Carme Balliu during the conference

A MUST-READ

Guide to the conservation and restoration of sculptures made from organic base materials Antoni Colomina Madrid: Síntesis, 2019, 193 p.

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Conservation and restoration of industrial heritage Santiago Arroyo, María Giménez and Diana Sánchez Madrid: Síntesis, 2018, 192 p.

This book provides a very instructive didactic, clear and well-structured guide to everything involving the restoration of sculptures made from organic base materials. The first pages include a brief section on various historical itineraries that contextualize the huge diversity of objects and sculptures that exist using these types of base materials.

There follows a description of the composition, atomic structure and properties of the different organic base materials used. Materials such as wood, cardboard, wax and ivory are described, with special emphasis on the treatment of synthetic organic plastics as an organic base.

The next chapter discusses the various techniques and creative processes most commonly used in these types of materials. It describes carving in wood, cardboard, stone and synthetic organic plastic, among others, as well as possible preparations, metal decorations and pictorial decorations. The book continues with two more sections that deal, firstly, with possible factors of deterioration and, secondly, with preventive conservation, a tool of great importance for the proper conservation of heritage.

Lastly, of note is a detailed explanation of the intervention methodology for the various organic base materials. The processes are divided into curative conservation and restoration itself and all the usual processes are described, from disinfection and disinfestation to the possible application of a final varnish. In short, this book is very useful as an introductory manual for professionals starting out in the field of conservation and restoration of sculptures made from organic base materials.

There is very little literature dedicated to the conservation and restoration of industrial heritage. The book, written by three authors with years of experience in the field, provides an overview of the methodology used on this type of heritage. Divided into five chapters, each describes simply but in detail in easy-to-read language, the different aspects that must be taken into account before carrying out any documentation, conservation, restoration and management tasks for this type of heritage. It starts with an introductory chapter that explains what industrial heritage is and the laws protecting it. The next chapter continues with a description of different types of immovable heritage, as well as the possible causes of deterioration. It continues with a third chapter, which sheds light on the conservation and restoration of movable heritage and its particularities, such as functionality and planned obsolescence. This is probably the most important chapter of the book, since it provides an overview of the subjects and issues from the perspective of a conservator-restorer, and serves as an introduction to the very little-known and highly valued speciality that is movable industrial heritage. The fourth chapter talks about the intervention methodology used in industrial heritage sites. From the point of view of an architect, it describes the keys for tackling restoration projects and offers examples where this methodology has been adopted. The fifth and final chapter gives a brief outline on how industrial heritage can be revitalized, in this case, not only regarding the material work itself, but the intangible value that its conservation and restoration contributes or can provide.

In summary, it is a useful introduction to the conservation and management of industrial heritage in general and is absolutely essential for anyone who has to carry out any type of intervention on movable industrial heritage, providing the theoretical basis that up to now has neve been compiled together in a single book.

Jordi Erra Picas, Curator of cultural artefacts specializing in sculptures and art historian

Mercè Gual,Conservator-restorer of cultural artefacts.

MNACTEC

centrederestauracio.gencat.cat

RESCAT

CRBMC. CENTRE DE RESTAURACIÓ DE BÉNS MOBLES DE CATALUNYA C. Arnau Cadell, 30 – 08197 Valldoreix Tel. 935 902 970 – Fax 935 902 971 crbmc.cultura@gencat.cat https://centrederestauracio.gencat.cat www.facebook.com/RestauraCat www.instagram.com/restaura.cat

PUBLISHED BY Ministry of Culture of the Government of Catalonia MANAGEMENT Àngels Solé EDITORIAL BOARD Esther Gual, Josep Paret, Àngels Planell, Pere Rovira,

Mònica Salas, Àngels Solé i Maite Toneu OVERALL COORDINATION Àngels Planell TEXTS Els seus autors COPY EDITING Àngels Planell i Sounds & Words PHOTOGRAPHY Ramon Maroto (CRBMC) and the authors themselves DOCUMENTATION Maria Ferreiro, Àngels Planell i Mònica Salas PHYSICOCHEMICAL ANALYSIS LABORATORY AND ANALYSIS PHOTOGRAPHY Ricardo Suárez X-RAY LABORATORY Esther Gual ORIGINAL GRAPHIC DESIGN ciklic COVER PHOTO Portrait of an old man in the village of Penelles (Noguera county) created during the Gargar festival, an example of rural street art.

Sabotaje al Montaje, 2016 LEGAL DEPOSIT B-13.856-2012 ISSN ONLINE EDITION 2013-3251 Key Title: Rescat (Barcelona, Internet) Abridged title: Rescat (Barc., Internet)

Generalitat de Catalunya Departament de Cultura