History Of Printing Printing Printing Process Colour Ink Paper Desktop Publishing Industrial Visit Book Binding
PRODUCTION PROCESS
COURSE FACULTY Faculty Bharat D Suthar Anchor Faculty Dr. Tridha Gajjar Programme Coordinator Graphic Design NID, Ahmedabad
ACKNOWLEDGEMENT I am grateful to our faculty Bharat D Suthar and anchor faculty Dr. Tridha Gajjar under whose guidance I learned a lot about printing, who with a lot of patience helped me get a clear understanding of all concepts. I would like to thank all my classmates who helped with ideating and have always given me constructive feedback. I would also like to thank Dilip Bhai, Sachin Bhai and everyone in the NID Print labs for their support during this module.
DOCUMENTATION BY Sindhura Thathaiah Ravindra S160115 Graphic Design PGDPD 2016-17
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CONTENTS
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History Of Printing Printing
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• Introduction to Printing
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• Conventional Printing
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• Types of Presses
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• Unconventional Printing
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Printing Process Colour
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• Colour Models
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• Colours In Printing
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Ink Paper
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• Types Of Paper
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• Paper Sizes
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• Grammage
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Desktop Publishing
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• Imposition
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• Binding
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Course Work Biblography
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HISTORY Woodblock printing Movable type Printing press Etching Lithography Chromolithography Rotary press Offset printing Hot metal typesetting Photostat and Rectigraph Screen printing Xerography Phototypesetting Inkjet printing Dot matrix printing Laser printing Thermal printing 3D printing Digital printing
200 1040 1440 1515 1796 1837 1843 1875 1884 1907 1910 1938 1949 1951 1968 1969 1972 1984 1993
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PRINTING INTRODUCTION The graphic arts industries try to achieve their common purpose - the reproduction of graphic images in large quantities- by selecting from shared techniques of preparation, printing, and assembly. The printing processes are at the core of this technology. Printing is a process of production of text and images, typically with ink on paper using a printing press. Each printing process uses a plate, or some form of image carrier, which transfers the ink image to the paper or substrate during printing. To do this, every printing plate in some way or another must be selective in picking up ink in the areas to be printed and rejecting ink in the non- printing areas. The essential differences among printing processes lie in the means by which they separate the image areas from the non-image areas.
Printing processes may be classified into two types: Conventional and Unconventional. The conventional printing processes produce numerous reproductions of an original subject by means of a printing press, which holds an inked image carrier and applies the pressure necessary to transfer the image to a substrate such as paper, paperboard, metal, plastic, cloth or glass. The unconventional printing processes include photography and non contact processes like electrophotography, thermal imaging and jet printing, which do not use conventional image carriers or presses.
PRINTING TECHNOLOGY Unconventional
Conventional
Letterpress
Lithography
Gravure
Screen
Electro Photography
Ionography Magnetography
Inkjet
Thermography
Photography
Flexography Continuous Dry Offset
Offset
Drop on Demand Sublimation
Ink (Liquid)
Powder Toner
Liquid Toner
Magnetic Liquid Toner Ink
Transfer
Hot-metal Color Donor Ink Ribbon/ Foil
Color Sensi Layer
Sheet or Web (substrate)
Originals
Pre- Press
Press
Post- Press
Printed Product
The main difference between the two types is that in the conventional process a single plate can produce number of reproductions on a press, while in the unconventional processes a new image must be generated for each reproduction, even if the identical subject is being reproduced.
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CONVENTIONAL PRINTING All conventional processes • Are impact printing methods - the master comes in contact with the substrate • Use a master- The master is an inked image carrier and applies the pressure to transfer the image to the substrate • Multiple copies can be made using the master • The image has two basic areas, which hold the ink that will produce the image, and the non-image areas, which remain uninked.
Relief Printing (Flexography/ Letterpress) The plate in relief printing has a raised surface on which ink is applied while non printing areas are depressed below the level that the ink rollers on the press reach. The paper is then pressed on the raised areas.
Planographic Printing (Lithography/ Offset) The plates have image and non-image areas on the same plane but separate the ink and non-printing areas by means of physiochemical principles; the image areas are ink receptive and the non-image areas are water receptive so they reject the ink.
Recess Printing (Gravure/ Intaglio)
Stencil Printing (Screen)
The plates or cylinders in gravure, have tiny depressions or wells that are filled with ink to be trasferred to the paper, while the non-printing areas are scraped clean of ink before the plate contacts the paper.
Screen or stencil image carriers have porous image areas through which the ink is forced; the ink is blocked in the nonimage areas.
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TYPES OF PRESSES Printing presses vary in size, construction and operation, depending upon many variables, such as type of product being printed, the number of products, and the kind of image carrier used. There are three basic types of presses, which differ in how they hold the image carrier and how they bring it in contact with the paper. They are platen, flat bed cylinder, and rotary presses.
Platen Presses In the platen press, used in letterpress printing, has a bed that holds the image carrier (metal type or plate) and a smooth platen that holds the paper. A vertical clamping contrivance clamps the bed, which carries the form into which the composed type is locked, and the platen, which carries the sheet of paper while it is being printed. When this clamping contrivance is open, the plate is inked by a series of rollers that descend and then ascend, and the printed sheet is removed and a new sheet placed in position on the platen.
Flat Bed Cylinder Presses Flat bed presses are used chiefly in letterpress and screen printing and proofing. The image carrier is on a flat bed. These presses are made with either verticals or horizontal beds and the paper is fed over a cylinder, which applies the transfer pressure. The cylinder provides the pressure while the plate retains its flat surface, generally in a horizontal position. Generally, too, the bed is mobile to allow the typeform, as it moves back and forth, both to pass under the rollers of the inking system and to pass under the impression cylinder around whose outer surface the sheet of paper is wrapped, attached by a set of clamps. Flatbed presses fall into various categories, depending on the cylinder’s operation.
Rotary Presses The paper is fed over one cylinder and the printing plate is mounted on another cylinder. The heavier plates used in letterpress must be curved so that they fit the contour of the cylinder. Lithography uses relatively thin wraparound plates, which fit into clamps on the cylinder. It is primarily used in high-speed, web-fed operations, in which the press takes paper from a roll, as in newspaper printing. Many of these large presses not only print as many as four colours but cut and fold and even bind in a cover—in one continuous automatic process.
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RELIEF PRINTING It is one of the oldest forms of printing. In relief printing, the image area is raised and the nonimage area is below the raised surface so that it does not contact the substrate in printing. Common examples of this type of printing are letterpress and flexography. The typewriter is also an example of relief printing. Impression surface Substrate (paper) Ink Raised printing surface Plate
Letterpress The letterpress is the oldest of the major printing processes. For hundreds of years, letterpress printing consisted of printing from metal type which is set by hand. Later, the letterpress plates were developed on the same principle- printing from a raised or relief surface. Taking an impression from a raised inked surface was the forerunner of all processes which today we refer to as “printing.� The principle is currently embodies in that process known as letterpress, and although some of the equipment and techniques are considered obsolete by mordern standards, they can still be found. In letterpress, the image looks inversed on the image area and thus prints properly on the substrate. The test is printed by metal movable type, relief blocks are made on zinc plate. The raised surface is inked be rollers and then pressed against the paper to get the impression. Elements are assembled together to create a form, which is locked inside a metal frame called chase. Letter press covers the gamut of printing from short- run job printing such as letterheads, billheads, envelopes, announcements, invitations, and small advertising brochures etc
R Film Negative
Hardened Emulsion
Plate
Acid Etch Hardened Emulsion Plate
Plate Wood Mount
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The three main categories of letterpress printing presses are platen, flatbed and rotary presses. Ink Fountain Roller
Platen Letterpress Two flat surfaces, the bed and the platen, make up this type of machine. The bed carries the image, which may be hand-set or cast metal type, or photoengraved plates, mounted together and locked into position. The platen provides a smooth surface on which the paper is held. The paper is pressed against the inked image to complete the transfer. The beds are vertical rather than horizontal, the plates are inked by inking rollers, and the impression is “pulled” on sheets fed manually or automatically over a platen.
Ink Fountain
Inking roller Ink Disc
Impression Platen
Image carrier
Paper
Flat Bed Cylinder Letterpress These presses are made with either verticals or horizontal beds. Presses may be one colour or two colour. On perfecting presses both sides are printed in one pass, the sheet being turned over between impressions. Type and plates are locked up on the bed as in a plated press, but the sheets are fed automatically over a cylinder, which also provides the necessary transfer pressure.
Inking roller
Feed Pile
Impression Cylinder
Ink Fountain Paper Sheets
Delivery Pile
Paper Image Carrier
Rotary Letterpress The greatest amount of letterpress printing - which includes a long - run commercial, packaging, newspaper, book and magazine printing - is performed on rotary presses. Web-fed rotary presses for periodical and book printing are either unit type or common impression cylinder (CIC). A unit press has a separate, complete printing unit for each colour. This system offers an advantage in multicolour printing: it allows more time between successive impressions, which improves the trapping of wet inks. The common impression cylinder consists of one large cylinder around which separate printing units are placed. For printing on coated papers, rotary presses are equipped with dryers. For printing letterpress newspapers, web-fed presses are built in couples which print both sides in succession, generally eight pages on a side with a four-page width to the web.
Paper Roll.
Inking roller Ink Fountain Inking roller Ink Fountain
Limitations
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• •
Folder
Plate Cylinder
Advantages -
•
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Plate Cylinder
Impression Cylinder
The Process Is Simple In Conception; The Image And The Non- Image Area Are Separated On Different Planes. Printing Can Be Performed Directly With Metal Type. Presses Are Available In A Wide Variety And Are Easily Adaptable To Special Purposes. Uniformity Of Colour Throughout The Run
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High Cost Of Photoengravings Direct Transfer Requires Smooth Printing Surfaces ( Coated Paper) Pressure Differentials, The Consequence Of Relief Images, Must Be Adjusted By Careful Makeready. In Multicolour Jobs Special Care Is Required To Ensure Good Trapping Of Wet Inks.
Flexography This process was first introduced in the early 1900s. Commonly referred to as flexographic or flexo printing, is a rotary relief printing process in which the image carrier is a flexible rubber or photopolymer plate or nylon with raised image areas. It uses water based or solvent based inks with a two roller inking system. Flexography combines features of letterpress and rotogravure in its use of relief plates and low-viscosity, fast drying inks. The presses are of three types: (1) Stack type, in which the printing units are placed vertically, the complete press usually consisting of two such stacks; (2) central impression cylinder, corresponding to the common impression cylinder letterpress used in magazine printing; and (3) in-line, corresponding to the unit- type magazine press. It finds its application largely in packaging products, including foil, tissue, paper, paperboard, corrugated board, and plastic film, can be printed with flexo.
Plate Cyl
Impression Cyl
Annilox Roll
Fountain Roll
The image shows a standard two roller system used in a stack press. There is a rubber fountain roller in the ink pan and an annilox roller, similar to the engraved gravure cylinder, for transferring the ink to the rubber plate on the plate cylinder.
Annilox Cells
Advantages
Cells per inch (CPI)- No. of cells in a linear inch. CPI - 140 to 1200 CPI When the annilox cell count increases, the amount of ink delivered is reduced. The annilox roller regulates how much ink is delivered to the plate. It depends on the CPI of the annilox roller.
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Relatively Inexpensive High printing speed Web and sheet feed presses Able to print on a variety of materials
Dry Offset Is a relief printing plate that transfers or “offsets” multiple colours to a rubber pad or “blanket”. The blanket then transfers an inked image to substrate. The process is called Dry offset because unlike the usual offset printing method, this method is printed dry – in the absence of water. Since it is relief printing, it does not need water. The ink roller just rolls one colour ( cyan) on the entire plate, then M, then Y, then K. This way each colour deposits in the intensity that is required. Each colour is applied in the required percentage in the required areas, then the plate is pressed together in order to mix the colour on the plate itself and then it is transferred on to the blanket and then onto the substrate.
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PLANOGRAPHIC PRINTING In planographic printing, the image and the non-image areas are essentially on the same level or surface. These areas are differentiated by means of chemistry, using the principle that water- based fluids and greasy substances such as inks tend not to mix. Image areas of the plate are made receptive to water-based solutions. Both substances are applied to the plate during printing, but each adheres only to its own area. This printing process is often called offset lithography or simply offset.
Lithography Printing Lithography is derived from the ancient greek work ‘Lithos’, means stone. In this process, the image areas are neither raised nor depressed, as in letterpress or gravure, respectively, but are on essentially the same plane surface of the printing plate as the non-image areas. The two areas are made grease- receptive and water- repellent (hydrophobic region), and the non-image areas are made water- receptive and grease repellent (hydrophilic region).
In the 1800s, lithographic printing was confined to direct printing on flat-bed presses to accommodate the heavy lithographic stones on which the image were hand drawn or hand transferred. A major change occurred in 1906, the offset lithographic press was invented. Previously the image had been transferred from the plate to the paper directly. On an offset press the plate image is first transferred to a smooth rubber surface called the blanket and then offset to the paper.
The basic press design includes the use of the three main cylinders to get the ink image onto the paper or other substrate. The first cylinder holds the printing plate; the second holds a rubber blanket which rolls against the ink plate, picking up the image; the third holds the substrate and rolls it against the inked plate to pick up the ink from it. The image is said to be “offset’ from plate to the blanket to the paper, rather than being printed directly from plate to paper.
Advantages •
Water Rollers
• Ink Rollers
• •
Plate Cylinder Water Offset Cylinder
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Limitations
Paper
• Impression Cylinder
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•
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The rubber printing surface conforms to the irregularities in the paper surface. The paper does not contact the metal printing plate, thereby reducing the abrasive wear and increasing the running life of plates. Printing speeds are increased. The image on an offset plate is straight reading instead of appearing in reverse. This facilitates both the preparation of the plates and the correction of errors. Less ink is required to obtain equal coverage. Able to print on both sides of a sheet in one pass. Introduction of computer to plate (CTP) machines has resulted in quicker plate making. Modern computer controlled presses can speed up the process of colour control and getting plates into accurate register.
The critical ink/water balance induces colour variations in the long runs and increases make ready waste. Since multicolour printing is wet on wet, trapping problems are frequently encountered, but less than in letterpress. In the impression nip ( the point where the paper and the blanket come in contact), the paper may fan out, resulting in poor register and sometimes producing wrinkles. The rubber blanket tends to distort in the nip, resulting in slur, doubling and spreading in halftones.
RECESS PRINTING Recess printing uses the principle that the slightest scratch or indentation upon a polished metal surface is capable of holding ink. When the surface is flooded with ink and the excess is wiped away, paper applied with sufficient pressure will withdraw the ink remaining in the depression.
Gravure The plates or cylinders in gravure, are the reverse of the letterpress; they have tiny depressions or wells that are filled with ink to be transferred to the paper, while the non-printing areas are scraped clean of ink before the plate contacts the paper. The plates used for gravure printing are called intaglio plates thus it is also referred to as intaglio printing. Gravure printing can be divided in to sheet- fed gravure and web-fed or rotogravure. In sheet-fed gravure, the image carrier is a metal plate, flexible enough to be wrapped around a plate cylinder. In web-fed gravure, the image is prepared directly on the surface of a copper-clad, steel-core cylinder, combining the functions of image carrier and carrier support in an integral unit.
Doctor Blade
Gravure Cylinder
Impression Cylinder
Ink Pan Filled Cells
Empty Cells
Image Area Gravure Cylinder
The printing cylinder rotates in a trough of liquid ink. During this motion, the inks ďŹ ll the cells of the cylinder and inks the image areas. However, the non-image areas also get inked as they are in relief. This excess ink is wiped clean by a blade called a doctor blade. The doctor blade is positioned at an angle over the cylinder so that when the cylinder rotates, the excess ink that was picked up by the non image areas are wiped clean. In the continuing motion of the cylinder, the paper (or the substrate) is fed in between the printing cylinder and the impression cylinder. By pressure, the ink in the cells is forced out onto the substrate. Since the printing image is made of copper, which is quite expensive, gravure is usually used for very long-run jobs which it handles well because the image is placed on the cylinder directly, and on copper, 104 Professional Prepress, Printing, & Publishing which is a strong metal. Traditionally gravure has been used by markets that have a need to produce long run and consistently good quality printing. Packaging and some long run publications therefore employ this printing process
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STENCIL PRINTING A method of transferring a pattern by brushing, spraying, or squeezing ink or paint through the open areas of any type of stencil. Screen or stencil image carriers have porous image areas through which the ink is forced; the ink is blocked in the non-image areas.
Blade Ink
Screen
Screen Printing
Template
The term screen printing is derived from the use of a porous screen made of finely woven fabric or metal mesh. Adhered is a stencil which blocks the openings in the screens in the areas which are not to be printed. During printing, the substrate is placed under the screen; the ink is applied to the screen and forced through the fine mesh openings in the areas not protected by the stencil, producing the image on the substrate.
The three basic elements of screen printing are the screen, the squeegee, and the ink.
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Paper
Base
Screen
Stencil
The photomechanical stencils are
The first main element of this type of printing is the fabric used. Screen printing used to be called silk screen printing or serigraphy earlier, because silk was the fabric used for many years. The fabrics used to make screens now are usually synthetic fabrics such a nylon, polyester, the industry has overcome the problems associated with the use of silk. Fabrics are available with thread counts from 10 to 200/cm. The fabric quality is determined by the thread thickness used.
The second element is the stencil, the pattern which determines what areas of the screen will transmit ink and what areas will not. The introduction of the photomechanical screen has made the process capable of rendering extremely fine detail, so that type as small as medium weight eight-point can be printed. The manual stencils are usually hand-cut stencils and masking stencils.
• Direct Stencil The direct stencil is made with PVA+ Ammonium bichromate or by Photo polymer coating. Light passes through the transparent areas and blocks the mesh squares as the coating hardens there. Light cannot pass through the black areas hence that area remains open.
• Indirect Stencil Special chromlin films are used with similar photoploymer coating on it. From the positive it makes the negative image on to the frame. Separate screens are made for separate colours. Generally black and Cyan are the two colours used for making the positive.
Squeegee The squeegee is the blade drawn across the screen to force ink though the mesh. This simple tool varies in the material of which it is made, the form and the size of the blade edge, the blade angle in relation to the fabric, and the pressure and speed with which it is drawn across the screen.
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1. 2. 3. 4. 5. 6.
2
3
4
5
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Square Edge for basic printing Rounded corner for more ink deposition U shape for heavy ink deposition in textile printing V shape for textural surfaces Bevel edge for printing on glass Ceramic surface
Screen frame
Advantages
The screen frame is a very important component, made of wood, aluminium, or steel. The frame supports the stencil fabric and allows for the proper degree of fabric tension. The relative tautness of the screen is a major determinant of accurate colour registration. Insufficient tension may also result in smearing or uneven ink deposit, and will eventually cause excessive wear on the screen.
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• •
• •
Since the printing surface in the screen printing process is very flexible, it allows printing on three dimensional objects too. A substrate that is two dimensional and flat is all that can be fed into those machines; in the case of screen printing, the printing surface itself can be wound around the substrate. So objects like cups, mugs, watches or other irregular shaped products can be done using the screen printing process. Printing by forcing ink through a stenciled screen mesh image directly onto substrate Principal applications: can print on any substrate; point-of purchase displays, billboards, decals, fabric, electronic circuit boards, glasses, etc. Ink formulation, screen mesh count, and image type are major quality factors Recognition characteristics: heavy, durable, brilliant layer of ink
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UNCONVENTIONAL PRINTING It is also referred to as non-impact printing since there is no physical contact between the substrate and in the unconventional processes a new image must be generated for each reproduction, even if the identical subject is being reproduced. Two types of nonimpact printers often used with computers are laser printers and ink-jet printers. These printers do not touch the paper when creating an image. Inkjet printers, use a series of nozzles to spray drops of ink directly on the paper. Laser printers, use dry ink (toner), static electricity, and heat to place and bond the ink onto the paper.
Types • • • • • •
Electrophotography or Xeroxography Ionography Magnetography Inkjet Thermography Photography
XEROXOGRAPHY
MAGNETOGRAPHY
Xeroxogrpahy which is also referred to as Electrography was invented by Chester Carlson in 1937, developed by Xerox Corporation. The artwork is placed face down on a glass plate and is illuminated by fluorescent light which travels length of the image. Reflected image is directed through the lenses in to a electrically charged drum. This charge leaks away where light from the image falls on the drum. This charge leaks away where light from the image fallen on the drum. A resin based powder (Toner) attracted to the image areas. This pattern of toner is transferred to the paper, where it’s fixed and fused by heat. Laser copier works like combined scanners and image setters by scanning the image digitally and using a laser to write the image onto electrostatic drum.
Magnetography (or ferrography), a method for printing letters, numbers, and other images on ordinary paper using magnetic powder. Magnetography is most frequently performed using an intermediate magnetic recording medium. In some devices the intermediate medium is a magnetic drum, along whose circumference are located the magnetic recording heads, developing section, contact roller, cleaning unit, and erase head. The magnetic drum revolves evenly during the operational cycle of the device. A latent magnetic image of the image is produced in the drum’s magnetic layer in the form of a mosaic of separate magnetic imprints generated by the magnetic recording heads. In the developing section, particles of a ferromagnetic powder are attracted to the magnetized portions of the drum surface, forming a visible image of the recorded symbols. Upon contact with the paper, the magnetic powder sticks to its surface. The resulting imprints are fixed by pressing the particles of powder into the paper surface by compression between rollers. To achieve better adhesion to the paper, the ferromagnetic material is coated with a thermoplastic resin and the rollers are heated. As the paper passes between the rollers, the resin melts and bonds the powder image firmly to the paper. Any powder remaining on the drum after the image has been transferred onto the paper is removed by the cleaning unit by fur brushes and a stream of air; the latent image is erased by the magnetic erase head and the drum is ready for a new recording. When several copies are required, the latent magnetic images are not erased and the printing process may be repeated for a virtually unlimited number of times.
IONOGRAPHY A type of in which the required electrostatically charged image is formed by the controlled projection of ions. Once expected to provide a lower cost than laser printers, ionographic printers are not now widely used.
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INK JET PRINTING Inkjet printing, like laser printing, is a non-impact process. Ink is emitted from nozzles while they pass over media. The operation of an inkjet printer is easy to visualize: liquid ink in various colors being squirted onto paper and other media, like plastic film and canvas, to build an image. A print head scans the page in horizontal strips, using the printer’s motor assembly to move it from left to right and back again, while the paper is rolled up in vertical steps, again by the printer. A strip (or row) of the image is printed, then the paper moves on, ready for the next strip. To speed things up, the print head doesn’t print just a single row of pixels in each pass, but a vertical row of pixels at a time. Most inkjets use thermal technology, whereby heat is used to fire ink onto the paper. There are three main stages in this process. The squirt is initiated by heating the ink to create a bubble until the pressure forces it to burst and hit the paper. The bubble then collapses as the element cools, and the resulting vacuum draws ink from the reservoir to replace the ink that was ejected.
Laser Printing
Comparison Of Inkjet And Laser Printing
This is electrophotographic imaging as in copying machines, with the printing machines driven by computers. When the document is sent for output, a laser beam charges the printing drum by applying a static charge to the photo receptive drum. The areas that received the charge tend to attract toner particles, and the image is transferred to substrate. For permanency, the toner-based image is heated and fused with the substrate.
Inkjet printing has two chief benefits over laser printers: lower printer cost and color-printing capabilities. But while inkjet printers are priced much less than laser printers, they are actually more expensive to use and maintain. Cartridges need to be changed more frequently and the special coated paper required to produce highquality output is very expensive. At a cost per page level, inkjet printing costs about 10 times more than laser printing.
THERMOGRAPHY Thermography is a modification of letterpress printing long used to imitate the engraved or embossed printing produces by the far more costly process of steel- die engraving. It is a print finishing process that produces a glossy, raised lettering by fusing thermographic print. A standard relief printing press is used, supplemented by special in -line equipment. The image is printed from ordinary raised type or relief plates using a special slow-drying ink. The sheet is then dusted with resinous powder which adheres to the tacky ink. After a suction device has removed powder for the uninked areas, the sheet passes through a heater of infrared light which fuses and dries the ink and resin and gives the raised image. The resin swells slightly as it is heated, so the final result is raised and slightly glossy printed image. It is often used to print stationery, invitations and calling cards. It is not appropriate for printing half tones or large areas of colour which are likely to have a pitted or mottled appearance. Edges of the text is not sharp and clear.
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COLLOTYPE It was invited in the 19th century. It was one of finest techniques used back then for reproduction of paintings. Collotype, or photogelatin printing, is a screen less planographic printing process capable of yielding almost photographic quality printing. Unlike most printing processes , it reproduces continuous tone images without the necessity
for converting them into halftone. In this process, a glass plate is first coated with lightsensitive gelatine solution and then exposed to continuous-tone negatives. It’s then soaked in glycerine, which is absorbed most in the non-harden areas. Hardened areas accept the ink and the plate can be used to print a few thousand copies of the positive image.
IDENTIFYING MAJOR PRINTING PROCESSES Letterpress • • •
The edges of the text will show ink squash due to heavy pressure Slight indentation on the flipside of the paper Ink intensity is higher than offset
Offset • • • •
Impression will be even in both text and halftone Lines and text have sharp and clear outline Solid colours are evenly inked Better reproduction than gravure
Gravure • • • •
•
The edges of text will not be sharp Saw tooth effect on the edges Rasterized text so quality is less then offset Reproduction of halftone dots is very precise because they are not pressed on the paper as they are in offset Image quality is better than offset
Screen • • •
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Heavy ink deposition happens, so the image is slightly raised impression Ink intensity is high and even Text is relatively blurry and low quality compared to text printed with the offset method
PREMEDIA
PRE- PRESS
PRESS
Printing Finishing
PRODUCT
Printing Process
PRINTED SHEET
Plate Making
PRINTING PLATE
Repro Preparation
FILM
Making the Original
ORIGINAL
PRINTING PROCESS
POST- PRESS
Each printing process can be divided into three major steps:
Pre- press
Press
Post- press
Prepress operations encompass that series of steps during which the idea for a printed image is converted into an image carrier such as a plate, cylinder, or screen. Prepress operations include composition and typesetting, graphic arts photography, image assembly, and image carrier preparation.
Refers to the actual printing operations
Post- press primarily involves the assembly of printed materials and consists of binding and finishing operations.
Foil Stamping Foil stamping, typically a commercial print process, is the application of pigment or metallic foil, gold or silver , but can also be various patterns or what is known as pastel foil which is an opaque color or white special lmbacked material, to paper where a heated die is stamped onto the foil, making it adhere to the surface leaving the design of the die on the paper. Foil stamping can be combined with embossing to create a more striking 3D image. Defects to be avoided are feathering, colour changes, scufďŹ ng, peeling and un-sharp edges.
Folding Folding largely completes postpress operations for certain products such as simple folded pamphlets. Other products are folded into bunches, known as signatures, of from 16 to 32 pages. Multiple signatures are then assembled and bound into books and magazines. Though folding is generally considered a postpress operation, most lithographic and gravure web presses are equipped with folders.
Embossing Embossing and debossing are the processes of creating either raised or recessed relief images and designs in paper and other materials. An embossed pattern is raised against the background, while a debossed pattern is sunken into the surface of the material (but might protrude somewhat on the reverse, back side). Defects that are commonly checked for are un-sharp edges, pinholes, ruptures and “halos� (shadows around the emboss).
Binding Binding is categorized by the method used to hold units of printed material together. The three most commonly used methods are adhesive binding, side binding, and saddle binding. Three types of covers are available to complete the binding process: selfcovers, socovers, and casebound covers.
Die Cutting Defects that are commonly checked for are clean cutting and correct positioning. Folding/ Bindery: Before the printed sheets are folded or bound it is common to make and review a trimmed dummy of the nished piece. Defects that are commonly checked for are page order and alignment.
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TYPES OF ORIGINALS LINE ART Line art or line drawing is any image that consists of distinct straight and curved lines placed against a (usually plain) background, without gradations in shade (darkness) or hue (color) to represent two-dimensional or threedimensional objects
CONTINUOUS TONE A continuous tone image is one where each color at any point in the image is reproduced as a single tone, and not as discrete halftones, such as one single color for monochromatic prints, or a combination of halftones for color prints. A gray scale or colour image format capable of illustrating continuous varying tonal range as opposed to line art. The most common continuous tone images are digital photographs.
DUO TONE
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HALF TONE Halftone is the reprographic technique that stimulates continuous tone imagery through the use of dots varying either in size, in shape or in spacing. ‘Halftone’ can also refer to the image that is produced by this process. Continuous tone imagery contains an infinite range of colors or greys, the halftone process reduces visual reproductions to an image that is printed with only one color. The resolution of halftone screen is measured in lines per inch (lpi). This is the number of dots in one inch, measured parallel with the screen’s angle. Known as the Screen Ruling, The resolution of a screen is written either with the suffix lpi or a hash mark. For example: ‘150 lpi’ or ‘150#’ The higher the pixel resolution of the source file, the greater the detail can be reproduced.
HALFTONE SCREEN
DENSITY
DENSITY RANGE
DENSITOMETER
A specially prepared glass screen or contact film screen which breaks the different grey tones of the original into a series of different sizes of dots.
Density is the level of darkness in a negative or positive film or print. The measurement of density is called densitometry.
The density range is the difference between the highest and the lowest density in of a photographic image.
An instrument called densitometer is used to measure density.
MOIRE PATTERN A moiré pattern is a secondary and visually evident superimposed pattern created, for example, when two identical (usually transparent) patterns on a flat or curved surface (such as closely spaced straight lines drawn radiating from a point or taking the form of a grid) are overlaid while displaced or rotated a small amount from one another. Moiré patterns are often an undesired artifact of images produced by various digital imaging and computer graphics techniques The moiré effect can be seen when looking through ordinary window screens at another screen or background. It can also be generated by a photographic or electronic reproduction, either deliberately or accidentally.
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COLOUR Colour and light are so closely related that it is impossible to have one without the other. The third part of this system is the observer. Colour is a combination of the physical sensation of light and the psychological interpretation of it. Physically, visible light is radiant energy having wavelengths in the range from about 400nm to 700nm. The equal combination of all wavelengths of visible light produces the sensation of white light.
Blue
400nm
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Visible light spectrum can be broken into three predominant bands of colour. These bands are RED (600-700nm), GREEN (500-600nm), BLUE (400-500nm). These are the primary colours of light. The way that light travels depends on the object they come in contact with. When light falls on any object, the colour a given object reflects is the colour the eye perceives as the colour of the object. The rest of the colours are absorbed by the object.
Red
500nm
Green
600nm
700nm
ADDITIVE PRIMARIES (RGB colour model) The colours Blue, green and red are called additive primaries. They are called so because when all 3 of them are mixed 100%, they produce white light and when mixed in different proportions produce different range of colours. Absence of all primary colour makes Black. In RGB, Additive colour model is used as white is the additive combination of all primary coloured lights. 24-bit colour in a high resolution monitor can display 16.7 million colours, human eye can see only 10 million.
RED + BLUE = MAGENTA (Complimentary to Green) RED + GREEN = YELLOW (Complimentary to Blue) GREEN + BLUE = CYAN (Complimentary to Red)
SUBTRACTIVE PRIMARIES (CMYK colour model) The colours Cyan, Magenta and Yellow are called subtractive primaries. When we subtract an additive primary colour from white light, the colour we have left is cyan, which is the additive mixture of blue and green light. Cyan, magenta, and yellow are the colours of printing inks with which we print colour reproductions. By overprinting selected amounts of cyan, magenta, and yellow the widest range of colours within the limitations of the paper and ink can be achieved. Most printing inks are transparent, that is, they allow light to pass through them to the paper. As the light passes through the ink, it is modified according to the characteristics of the ink. The paper then acts as a reflecting surface which reflects the light back and through the ink to the eye. CYAN + MAGENTA= BLUE (Complementary to Yellow) MAGENTA+ YELLOW = RED (Complementary to Cyan) YELLOW + CYAN = GREEN (Complementary to Magenta)
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BEHAVIOUR OF PRINTING INKS
CYAN INK Absorbs Red Reflects blue and green
MAGENTA INK Absorbs Green Reflects blue and red
YELLOW INK Absorbs blue Reflects green and red
BLACK INK Absorbs red, blue, and green.
GAMUT A gamut is a range of colours that a colour system can display or print. Different colour spaces have different gamuts, as do different devices. When a colour falls outside of a colour space’s gamut in this way, it can’t be reproduce by the device and is called “out of gamut. The spectrum of colours seen by the human eye is wider than the gamut available in any colour model. Among the colour models used in Photoshop, L*a*b has the largest gamut. Typically, RGB gamuts contain the subset of these colours that can be viewed on a computer or television monitor (which emits red, green, and blue light). Therefore, some colours, such as pure cyan or pure yellow, can’t be displayed accurately on a monitor. CMYK gamuts are smaller, consisting only of colours that can be printed using process colour inks.
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Visible Spectrum Pantone RGB CMYK
METHODS OF PRINTING COLOUR ON PAPER
L*a*b COLOUR MODEL The L*a*b colour model is based on the model proposed by the Commission Internationale d’Eclairage (CIE) in 1931 as an international standard for colour measurement. In 1976, this model was refined and named CIE L*a*b. It consists of a luminance or lightness component (L) and two chromatic components– a component (from green to red) and the b component (from blue to yellow). L*a*b colour is designed to be device independent, creating consistent colour regardless of the device (such as monitor, printer, computer, or scanner) used to create or output the image.
HSB COLOUR MODEL Based on the human perception of colour, the HSB model describes three fundamental characteristics of colour: HUE - is the colour reflected from or transmitted through an object. It is measured as a location on the standard colour wheel, expressed as a degree between 0 and 360. In common use, hue is identified by the name of the colour such as red, orange or green. SATURATION - sometimes called Chroma, is the strength or purity of colour. Saturation represents the amount of gray in proportion to the hue, measured as a percentage from 0% (gray) to 100%(fully saturated). On the standard colour wheel, saturation increases from the center to the edge. BRIGHTNESS - IS the relative lightness or darkness of the colour, usually measured as a percentage from 0%(black) to 100%(white).
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SPOT COLOUR A spot colour is a special premixed ink that is used instead of, or in addition to, process inks, and that requires its own printing plate on a printing press. Use spot colour when few colours are specified and colour accuracy is critical. Spot colour inks can accurately reproduce colours that are outside the gamut of process colours. However, the exact appearance of the printed spot colour is determined by the combination of the ink as mixed by the commercial printer and the paper it’s printed on, not by colour values you specify or by colour management. When you specify spot colour values, you’re describing the simulated appearance of the colour for your monitor and composite printer only (subject to the gamut limitations of those devices). Keep the following guidelines in mind when specifying a spot colour: • For best results in printed documents, specify a spot colour from a colour-matching system supported by your commercial printer. • Minimize the number of spot colours you use. Each spot colour you create will generate an additional spot colour printing plate for a printing press, increasing your printing costs. If you think you might require more than four colours, consider printing your document using process colours. • You can use a spot colour printing plate to apply a varnish over areas of a process colour job. In this case, your print job would use a total of five inks—four process inks and one spot varnish.
•
If an object contains spot colours and overlaps another object containing transparency, undesirable results may occur when exporting to EPS format, when converting spot colours to process colours using the Print dialog box, or when creating colour separations in an application other than Illustrator or InDesign. For best results, use the Flattener Preview or the Separations Preview to soft proof the effects of flattening transparency before printing. In addition, you can convert the spot colours to process colours by using the Ink Manager in InDesign before printing or exporting.
FOUR COLOUR PRINTING Four colour process printing is a system where a colour image is separated into 4 different colour values (called a colour separation) by the use of filters and screens. This used to be done with photographic film on a graphic arts camera, but is usually done digitally with software now. The result is a colour separation of 4 images that when transferred to printing plates and sequentially printed on a printing press with the coloured inks cyan (blue), magenta (red), yellow and black (the k in cmyk), reproduces the original colour image. Most of the entire spectrum or gamut of colours are reproduced with just the four process ink colours. The four colour printing process is universally used in the graphic arts and commercial printing industry for the reproduction of colour images and text.
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Features • • • •
Uses same 4 standardized base colours all the time (Cyan, Magenta, Yellow and Black) Small dots of these colours are printed at different angles to create the printed image Most widely used and cost effective colour system in commercial printing Significantly cheaper than toner based printing for larger quantity runs
HEXACHROME PRINTING Hexachrome is a six-colour process printing system with a specially enhanced colour ink set. It was introduced in 1994. With Hexachrome, you can now reproduce rich, vibrant solid colours, realistic skin tones and elegant pastels. The Hexachrome colour gamut exceeds that of CMYK, In addition to custom CMYK inks, Hexachrome added orange and green inks, allowing you to achieve the same bright, vibrant colours on press with which you design on your computer. Hexachrome reduces your dependency on spot colours and allows you to easily re-purpose your designs for different applications, including the Web! Hexachrome is supported by many technology partners, ink manufacturers, software developers, proofing systems and printing devices. . It is therefore also known as a CMYKOG process.
PROCESS COLOUR Most printing inks are transparent; that is, they allow light to pass through them to the paper. As the light passes through the ink, it is modified according to the characteristics of the ink. The paper then acts as a reflecting surface which reflects the light back through the ink to the eye. Each process - colour ink absorbs one of the components of the light passing through and transmits the other two components to the paper so that they may be reflected back to the eye. This method of achieving colour in printing is referred to as CMYK, four– color process, 4/c process or even just process. To reproduce a colour image, a ďŹ le is separated into four different colours: Cyan (C), Magenta (M), Yellow (Y) and Black (K). During separation, screen tints comprised of small dots are applied at different angles to each of the four colours. The screened separations are then transferred to four different printing plates, one for each colour, and run on a printing press with one colour overprinting the next. The composite image fools the naked eye with the illusion of continuous tone. A process colour is printed using a combination of the four standard process inks: cyan, magenta, yellow, and black (CMYK). Use process colours when a job requires so many colours that using individual spot inks would be expensive or impractical, as when printing colour photographs.
CMYK Colour
Cyan
Yellow
Black
SCREEN TINTS Different tints of the same colour can be produced by applying a percentage of screen tint to an image or to text. By utilizing screen tints, you can create the illusion of a multicolour job using a single ink colour.
100% 90% 80% 70% 60% 50% 40% 30% 20% 10%
Magenta
27
28
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INK Printing inks are, according to their viscosity, divided into • Liquid Inks • Paste Inks
Liquid inks are employed in gravure and flexo printing, while paste inks are used in letterpress and lithography. Screen inks are intermediate between paste and liquid inks. Basically, all printing inks are made up of • Colourant • Vehicle (Or Varnish) • Solvent • Additives.
COLOURANTS are grouped into • Pigments (tiny crystals, insoluble in the vehicle) and • Dyestuffs (soluble).
Pigments Pigments are the visible portion of the ink. They may be in powder form (dry toner), in a concentrated paste dispersion known as a flush, or in a liquid dispersion. Important characteristics of pigment include specific gravity, particle size, opacity, chemical resistance, wettability, and permanence.
VEHICLES are made up of oils (petroleum or vegetable), solvents, water, or a combination of these, they carry the colorant through the printing press and attach it to the paper or substrate. Most vehicles contain resins which serve to bind the colorant to the printing surface. The vehicle is responsible for an ink’s body and viscosity, or flow properties. It is also the primary factor in transfer, tack, adhesion, lay, drying and gloss.
SOLVENTS are used to dissolve the binders of printing inks. They are also used, by the manufacturer and by the printer, to adjust the viscosity of the ink to the printer’s requirements. The solvents used in printing inks include mineral oil, other aliphatic and aromatic hydrocarbons, ketones, esters, and alcohols. These substances do not take part in any chemical reaction.
ADDITIVES can include waxes, driers and other materials which add specific characteristics to an ink or to the dried ink film, such as slip and resistance to scuffing and chemicals.
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Dye Are soluble in the material they are used in.
INK CHARACTERISTICS BODY
TACK
VISCOSITY
Body Consistency of the ink. On prolonged exposure to air and the increase in heat produced by the roller, the consistency may vary from time to time.
Stickiness of the ink. Resistance of the ink film to split. Splitting occurs when the ink from printing plate is transferred to the printing blanket. Improper transfer leads to bad quality of print.
Degree at which ink resists the flow under force. Viscosity also can change with the frictional and heat generated by the roller train. Inkometer is used to measure the viscosity.
TINTING STRENGTH
OPACITY
LENGTH
Covering power of the ink. Different pigments have different degrees of opacity because of the substances used ti produce the pigments.
Ability of the ink to flow. Necessary for the ink to move properly through the roller train of the press to achieve best results.
Ability of the ink to produce a tint with addition of white pigment
PERMANENCY The degree in which printed ink resists the fading power of light. The rate that an ink fade is known as degree of light fastness and is especially important when printed items, will be exposed to a high level of light.
DRYING OF INK ABSORPTION
OXIDATION
HEAT
Ink dried by absorption when printing application complete on absorbing surface such a s newspaper printer corrugated board.
Comes in contact with oxygen of atmosphere and converting the ink on film on substrate to a solid
The heat sets ink dry by evaporation in hot air dryers
INK RELATED PROBLEMS SETOFF
INK ADHESION
MOTTLING
CRYSTALLISATION
The transfer of ink from sheet to back of the next sheet. Caused by too much ink being applied or slow drying.
Result of set-off and slow drying ink, which in turn usually the result of poorly adjusted press settings.
Uneven appearance in the solid area of the printed document caused by uneven distribution of ink, non absorbent papers or faulty press adjustments.
Time between each color printing is more and if ink dry, it will not accept the next color.
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PAPER The word paper is derived from the word ‘papyrus’. The papyrus plant was found in Egypt. 5000 years ago, Egyptians created “sheets” of papyrus by harvesting, peeling and slicing the plant into strips. Paper as we know it today originated in China. Traditional Chinese records gives credits for its development to T’sai Lun who was even defined as the god of papermakers.
Paper is a natural product because it is manufactured from a natural and renewable raw material, wood. It also has another big environmental advantage, it is 100% recyclable.
UNCOATED
COATED
Uncoated stock is paper that has no coated pigment applied to reduce the absorbency or increase the smoothness. The uncoated nishes can be described as vellum, antique, wove, or smooth. Uncoated paper is not shiny, not coated, inexpensive, easy to read, easy to write on, pen ink won’t smear and looks flat. Almost all coloured paper is uncoated.
A coated stock has a surface coating that has been applied to make the surface more receptive for the reproduction of text and images in order to achieve sharper detail and improved color density. By adding a coated clay pigment, the objective of coating the stock is to improve the smoothness and reduce the absorbency. Coated paper can be categorized as matte, dull, cast, gloss, and high gloss. The coating can be on both sides of the stock (coated two sides, “C2S”) or on one side only (coated one side, “C1S”). From these subcategories, paper stocks are then separated into types such as offset, bond, cover, index, and vellum bristol. The following tables show these types, along with their common colors, weights, and uses. Coated paper starts out as uncoated. After the coating is applied, the sheet can be left alone, in which case it’s called a “dull” finish. If the sheet is buffed to a shine, IT’s called “gloss”.
MATTE These papers have a thin coating applied which is not buffed to a shine. It is often described as having a “dull” finish.
Coated Paper
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Uncoated Paper
TYPES OF PAPER NEWSPRINT
WOVE PAPER
BOND PAPER
•
It is writing paper with a uniform surface, faint mesh pattern within the grain, not ribbed or watermarked, used in text book, coloured paper used in bill or record paper.
A high quality, durable writing paper similar to bank paper but having a weight greater than 50g/m2. It is now used for letterheads and other stationery and as paper for electronic printers. It is largely made from rag pulp which produces a stronger paper than wood pulp.
OFFSET PAPER
CARTRIDGE PAPER
ART PAPER
Paper produced primarily for use on offset presses, generally possessing characteristics vital on the printing process such as dimensional stability, cleanliness, pick resistance, etc. It is also called lithographic paper. It is rough on both sides, more rag content, good for folding.
A thick white paper, with stiff feel, more rag content, preserved for long time, used in sketchbook, certificates, stamp paper. An uncoated type of drawing or printing paper, usually made from bleached sulphate wood pulp with an addition of esparto grass.
China clay coating covers porous surface, gives smooth finish, less absorption of ink, gives smooth finish, less absorption of ink, gives good ink depth, can be matt or gloss finish.
INKJET PAPER
PHOTO PAPER
GREYBOARD
RECYCLED PAPER
Is paper designed for inkjet printers, typically classified by weight, brightness, and smoothness, and sometimes by its opacity.
Is a category of inkjet paper designed specifically for reproduction of photographs. Photo paper is usually divided into glossy, matte or silk finishes.
Lines or unlined board made from waster paper. It has a rough texture, good bulk and its grey in colour. Used for packaging material or covers for publications.
• •
•
•
It is low-cost, low-quality, non-archival paper. It is generally made by a mechanical milling process, without the chemical process. The lignin causes the paper to rapidly become brittle and yellow when exposed to air and/or sunlight. It is used in the printing of newspapers, flyers and other printed material for mass distribution. It usually has an off-white cast and distinctive feel.
• •
•
Made from waste paper, usually mixed with fresh wood pulp If paper contains ink, it must be deinked. This also removes fillers, clays, and fiber fragments. Almost all types of paper can be recycled today, but some types are harder to recycle than others. Kraft paper, papers coated with plastic or aluminium foil, and papers that are all waxed, pasted or gummed are usually not recycled because the process is too expensive. Different types of paper are usually sorted before recycling, such as newspaper and cardboard boxes.
TRACING PAPER
MAP LITHO
DUPLEX BOARD
CHROMO PAPER
MIRROR COAT
CARD
It is translucent and resistant to oil grease.
Top surface is smoother, used for books and leaflets.
Box board, used in cartons.
One side coated, used for labels, wrappings.
Coated with china clay, mirror finish.
Thicker paper are called cards. Usually paper over 220gsm are referred to as cards.
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PAPER SIZES Paper standards Basically two types, British standards and International standards. Foolscap - 13.5”x17” Demy- 17.5”x22.5” Medium- 18”x23” Royal- 20”x25” Crown- 15”x20” Imperial- 22”x30”
4to
Folio
When paper is divided into half on the longer side, it is called the Folio. Half of folio is know as 4to, half the above is 8vo and so on.
A SERIES A SERIES ISO paper sizes are all based on a single aspect ratio of square root of 2, or approximately 1:1.4142. The base A0 size of paper is has an area of 1 m2. Rounded to the nearest millimeter, the A0 paper size is 841 by 1,189 millimeters (33.1 in × 46.8 in). Successive paper sizes in the series A1, A2, A3, and so forth, are defined by halving the preceding paper size across the larger dimension. The most frequently used paper size is A4 measuring 210 by 297 millimeters (8.27 in × 11.7 in). A0 - 841 mm x 1189 mm A1 - 594 mm x 841 mm A2 - 420 mm x 594 mm A3 - 297 mm x 420 mm A4 - 210 mm x 297 mm A5 - 148 mm x 210 mm A6 - 105 mm x 148 mm
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16vo 8vo 32mo
B SERIES B SERIES The area of B series sheets is the geometric mean of successive A series sheets. So, B1 is between A0 and A1 in size. As a result, B0 is 1 metre wide, and other sizes in the B series are a half, a quarter or further fractions of a metre wide. While less common in offi ce use, it is used for a variety of special situations. Many posters use B-series paper or a close approximation, such as 50 cm × 70 cm; B5 is a relatively common choice for books. The B series is also used for envelopes and passports. The B-series is widely used in the printing industry to describe both paper sizes and printing press sizes, including digital presses. B3 paper is used to print two US letter or A4 pages side by side using imposition; four pages would be printed on B2, eight on B1, etc.
B0 - 1000 mm x 1414 mm B1 - 707 mm x 1000 mm B2 - 500 mm x 707 mm B3 - 353 mm x 500 mm B4 - 250 mm x 353 mm B5 - 176 mm x 250 mm B6 - 125 mm x 176 mm
C SERIES C SERIES The C series is used only for envelopes and is defi ned in ISO 269. The area of C series sheets is the geometric mean of the areas of the A and B series sheets of the same number; for instance, the area of a C4 sheet is the geometric mean of the areas of an A4 sheet and a B4 sheet. This means that C4 is slightly larger than A4, and B4 slightly larger than C4. The practical usage of this is that a letter written on A4 paper fi ts inside a C4 envelope, and C4 paper ts inside a B4 envelope.
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PAPER GRAIN Paper, like wood, has a grain. If a book is printed with the paper grain parallel to the spine it will open more easily. Adhesive binding on paper with the wrong grain direction can produce disastrous results. Here are some simple tests to determine paper grain direction:
FOLDING TEST When folding a small sheet of paper you will notice that it folds more easily and smoothly when the fold is parallel to the grain. If folded against the grain, the small ber particles break and make an unsatisfactory fold.
MOISTURE TEST If moisture is applied to one side of a sheet of paper, it immediately starts to curl in one direction. The expansion is on the cross-grain edge, the curl indicating the paper grain direction.
BENDING TEST Thicker papers are best tested by bending them in both directions. One direction oers considerably more resistance than the other. Parallel to the grain direction the resistance is far less than against the grain.
TEARING TEST A sheet is torn in longitudinal and transverse directions. The tear pattern will be straight when parallel to the grain and jagged across the grain.
GRAMMAGE The weight of paper in countries that use ISO paper sizes is defined by ISO536 paper and board - Determination of Grammage. This standard defines grammage as grammes per square meter 9g/m2). Thus the weight of a single sheet of A0 paper defines the grammage of that paper type as the A0 size is defined by the ISO216 as having an area of 1 square meter. An A0 sgeet of 80gsm paper will weigh 80grams. Newspaper ranges between 45gsm to 50gsm. Usually the highest grammage paper available is 550gsm.
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CALCULATING WEIGHTS A convenient feature of the ‘A’ size range is that the area of an A0 sheet is one square meter. Since the weight of paper is specified in grammes per square meter it is relatively easy to calculate the weight of an A size document.
DESKTOP PUBLISHING Paper, like wood, has a grain. If a book is printed with the paper grain parallel to the spine it will open more easily and lay at. Adhesive binding on paper with the wrong grain direction can produce disastrous results. Here are some simple tests to determine paper grain direction:
PAGINATION number of pages in a document
DUMMY: folded paper that represents a document
WORK AND TURN: a sheet of paper is printed on its fi rst side and then turned over LEFT TO RIGHT and printed on the back side. WORK AND TUMBLE: a sheet of paper is printed on its fi rst side and then turned over TOP TO BOTTOM and printed on the back side.
IMPOSTITION An imposition is the master plan for the assembly of printed images into a finished piece. In prepress, “imposition” means the arrangement of pages on the press sheet so that when folded the pages read consecutively, obtain faster printing, simplify binding and reduce paper waste. How you arrange the pages on the sheet depends on the sizes of the press sheet and the pages, how the job will be founded and bound. . Correct imposition minimizes printing time by maximizing the number of pages per impression, reducing cost of press time and materials. To achieve this, the printed sheet must be filled as fully as possible.
The type of imposition used depends on several factors.
1. The design of the printed piece – • Whether it is multicolour, process colour, or single colour. • Whether one or both sides of the sheet are to be printed. • Whether one or several duplicate images are to be reproduced on the same sheet • The type of finishing operations that are required, such as folding, trimming, and binding.
2. The type and size of the press to be used. Whether the press is sheet fed or web fed, and if the job is ganged, the soze of the press sheet, and whether to use a large sheet or a single unit. 3. The type of paper to be used during printing. Whether the image position in relation to grain direction will affect folding operations. The grain of the paper should always run parallel to the first fold.
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TYPES OF IMPOSITION One -side imposition
eventual binding edge
7
10
8
9
11
6
Paper, like wood, has a grain. If a book is printed with the paper grain parallel to the spine it will open more easily. Adhesive binding on paper with the wrong grain direction can produce disastrous results. Here are some simple tests to determine paper grain direction:
12
third fold
second fold
4
13
3
14
16
1
15
2
Sheet wise imposition Two printing plates are used in sheet wise imposition. One printing plate is used to print on one side of a press sheet. A second plate is used to print on one side of a press sheet. A second plate containing different information is then made, the sheets are turned over, and the sheets are printed on the other side from the second plate.
1
3
5
7
8
6
4
2
9
11
13
15
16
14
12
10
Front of Signature
Ganged imposition Often the job to be printed is smaller than the press can handle, or it is so much smaller than the standard press sheet size that printing only that one job on each press sheet would be very inefficient use of equipment. When a press sheet carries only one job, it is called one-up imposition. When more than one job is run on the same sheet, it is called two-up, three-up, four-up, and so on, depending on the number of final jobs run on each press sheet. It makes no difference if the same or different images are printed; the same terms are used.
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Back of Signature
TRAPPING Trapping is a measure of how well one ink printed on top of another. With the advent of Pre-press Software the termed is used to describe the compensation for misregistration between printing units on a multicolour press. The misregistration causes unsightly gaps or white space on the ďŹ nal printed work. Trapping involves creating overlaps (spreads) or underlaps (chokes) of objects during the print production process to eliminate misregistration on the press.
FOLDING Folding machines are designed to make two basic types of folds– right angle and parallel folds.
Single Fold
Letter Fold
Double Parallel Fold
Engineering Fold
Gate Fold
Map Fold
4 Page Standard Fold
8 Page Fold
Z Fold
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BINDING Book binding is the process of physically assembling a book from a number of folded or unfolded sheets of paper or other material. The imposition of design depends in part on the binding method. Some of the most popular binding methods include: Perfect binding, saddle-stitching, collate and cut.
BINDING Library
Stationery
Wire Stitching
Center Stitch
Side Stitch
Office Stationery
Pads
Cut Board Binding
Flexible Spiral Ledger Binding Binding
Wire-o
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Soft Cover
Loose Leaf
Round Spiral
Comb Spiral
Hard Cover
Flexible Binding
Spiral Binding
Full Binding
Flat Back
Round Back Folding Gathering Section Sewing Gluing End Paper Pasting Rounding Backing Head Band Pasting Linen Pasting Case Making Casing
POSTER - OFFSET AND SCREEN PRINTING Brief Finished Size - 13.125 X 17.5 inches Background printing method - Offset Printing (single colour) Foreground printing method - Screen Printing (single colour) Understand the printing process and design the poster accordingly and make print ready files keeping in mind the two printing methods.
We used text to understand how offset printed text looks. Screen printed a thin border made of halftone dots to see how halftone looks in screen printing and if tiny dots will translate well on print and to explore the constraints of registration in offset. The shadow of the stamp is made of two layers, a solid orange (offset) and blue dots (screen), to see if overlaying them will make them look like a third colour in print. Gray scale image printed in offset.
Half tone dots printed in offset.
Solid colour vector printed in offset. Half tone lines printed in offset.
Orange areas printed in offset.
Blue areas printed in offset.
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The final poster was colour seperated.
In order to send it to print, Offset image area is made grey scale, in order to make the negative for the plate. The screen print final file is made in black and white inorder to make a perfect negative for printing.
Offset print file
Screen print file
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BOOK BINDING PAD BINDING
PERFECT BINDING
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CENTRE STITCH - HARD BINDING
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COSTING PROBLEM Calculate the cost of printing booklet from following specification. What is printing? 1500 copies 14cm X 21cm, No bleed 21cm X 28 cm 128 pages + 4 page cover Bilt Sinar Art Paper 130gsm for inside pages and 210 gsm for cover Soft cover, section sewing and cover pasting at spine (perfect binding)
Name of the job: Quantity Finished size: Open Size No. of pages: Paper: Binding:
No. of colours: Paper cost:
Printing cost: Binding cost:
Cover 4 + 1 colour Inside pages - single colour print Rs. 2300 per ream for 23” X 36” X 130gsm Rs. 3000 per ream for 30” X 40” X 130 gsm Rs. 6000 per ream for 23” X 36” X 210 gsm Four colour Rs. 3200 and single colours Rs.1000 per 1000 copies Rs. 12 per book
SOLUTION
(A)
(B)
23” X 36” sheet fits 8 spreads
30” X 40” sheet fits 9 spreads
Cost of Inside Pages:
Cost of Inside Pages:
(8X2) = 16 | (16X2) = 32 pages 1 book = 128 pages | 128 pages/ 32 = 4 sheets 4 sheets X 1500 copies = 6,000 sheets 6,000 sheets required, 500 sheets per ream 6,000/500=12 reams
(9X2) = 18 | (18X2) = 36 pages 1 book = 128 pages | 128 pages/ 36 = 3 sheets 3 sheets X 1500 copies = 4,500 sheets 4,500 sheets required, 500 sheets per ream 4,500/500=9 reams
1 ream = Rs 2300 12 reams = 12X2300 = Rs 27,600 + 2300 (1 ream for wastage) = Rs 29,900 Cost of cover:
1 ream = Rs 3000 9 reams = 9X3000 = Rs 27,000 + 3000 (1 ream for wastage) = Rs 30,000 Cost of Printing
Size of 210gsm ream is 23” X 36” 8 covers fit in 1 sheet Requirement is 1500 covers 1500/8 = 188 sheets = round off 200 1 ream = 500 sheets 200/500 = 0.4 reams 1 ream = Rs 6000 0.4 ream = 0.4 X 6000 = Rs 2400
130gsm sheet dimensions
23” X 36” sheet fits 8 spreads
(C)
4 colour printing per copy is Rs 3.2 1 colour printing per copy is Re. 1 Inside pages : No. of inside pages for (23” X 36”) - 4 sheet per copy = 8 plates = 8 X 1000 = Rs 8000 X 2 = 16,000 No. of inside pages for (30” X 40”) - 3 sheets = 6 plates = 6 X Re. 1000 = Rs 6000 X 2 = 12000 Since we make 1500 copies, printer considers it at 2 lots of 1000 copies each. thus 2000 copies Cover : No. of cover pages (Rs. 3200 X 2 = 6400) + ( Rs 1000 X 2 = 2000) = Rs 8400
30” X 40” sheet fits 9 spreads
= Total Cost ( Rs) Inside pages paper cost + Cover cost+ Inside pages Print+ Cover page Print + Binding Cost
29,900
30,000
2400 16,000 8400 18,000
2400 12,000 8400 18,000
23” X 36” sheet
23” X 36” sheet
74,700
70,800
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INDUSTRIAL VISIT Art-O-Print is a partnership firm established in April 1996. The company specialises in printing and packaging materials with facilities equipped to manufacture large and small volumes of various products - Packaging Material, Braille on Pharmaceutical Packaging, Pharma Outserts, Pharmaceutical Product Packaging, Pharmaceutical Product Display Kit, Custom Sample Sachet, Pharma Product Display, Portable Batch Counter, Printed PopUp Card, Paper Bag, to name a few. Machines we observed were • 4 colour offset machine • 6 colour offset machine • CTP machine • Die cutting machine • 2 color machine with 1 colour printed on each side • Inventory storage area • Roll cutting machine • Automatic pasting machine etc.
The field visit was a great experience since we saw the exact working of the offset machines and could get a better understanding of what we learnt theoretically. It also helped us understand how a large printing facility functions.
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BIBLOGRAPHY Graphic Arts Manual by Janet Fields https://www.britannica.com http://encyclopedia2.thefreedictionary.com http://www.image-specialists.com http://www.prepressure.com/images/printing-press-offset-sheetfed.jpg http://www.devonintl.com/devon-packaging/images/fullsize/printing-offset.gif http://www.dryoffset.com/images/plastics/figure2.jpg http://www.stampcommunity.org/uploaded/jorgesurcl/20130120_zzDOL.JPG http://www.colorprintingforum.com/attachments/direct-imaging-offset-press/22d1158536101-why-didheidelberg-discontinue-di-presses-directpress.jpg http://www.colorprintingforum.com/attachments/indigo-digital-press/175d1226133255-hp-indigo-vskonica-minolta-biz-hub-pro-how-indigo-press-works.jpg http://blog.graphicmatter.com/wp-content/uploads/2011/05/Printing_Offset.jpg http://photoshop911.com/tutorials/screen_print_seps/screen_print_diagram.png http://legendsmade. com/?page_id=16 http://www.myprintguide.org/glossary/images/Computer-To-Plate-(CTPe).gif http://machouse.ua/pub/files/193/92/1.jpg http://read.pudn.com/downloads194/sourcecode/math/911252/ImageHalftoningFloyd
SPECIFICATIONS Page Dimensions A4 - 210X 297 mm Headline Typeface Raleway Bold 24pt Body Text Typeface Raleway set in 11 pt and 8pt Raleway was designed by Matt McInerney
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