PR IN T ING
COURSE DOCUMENTAT ION BY PAYAL VATS [1]
c O N T E N T S
PRINTING MOVABLE TYPE PRINTING IN INDIA CLASSIFICATION OF PRINTING CONVENTIONAL PRINTING NON CONVENTIONAL PRINTING OFFSET PRODUCTION SYSTEM COLOUR AND INKS IN PRINTING BINDING AND TERMINOLOGIES IMPOSITION AND TYPES PAPER INPRINTING CASE STUDY SOURCES INFORMATION
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What is printing?
It is a process of producing text/ images on paper, typically with ink using a printing press. It is often carried out as a large- scale process, and is an essential part of publishing and transaction printing. A printing press is a mechanical device for applying pressure to an inked surface resting upon a medium (such as paper or cloth), thereby transferring an image. The mechanical systems involved were first assembled in Germany by the goldsmith Johannes Gutenberg around 1440, based on existing screw-presses used to press cloth, grapes, etc. and possibly prints. Gutenberg was the first in Western Europe to develop a printing press. During the Renaissance era, printing methods based on Gutenberg’s printing press spread rapidly throughout first Europe and then the rest of the world. It eventually replaced most versions of block printing, making it the most used format of modern movable type, until being superseded by the advent of offset printing
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Movable type
Movable type is the system of printing and typography using movable pieces of metal type, made by casting from matrices struck by letter punches. Compared to woodblock printing, movable type page setting was quicker and more durable for alphabetic scripts. The metal type pieces were more durable and the lettering was more uniform, leading to typography and fonts. The high quality and relatively low price of the Gutenberg Bible (1455) established the superiority of movable type, and printing presses rapidly spread across Europe, leading up to the Renaissance, and later all around the world. Today, practically all movable type printing ultimately derives from Gutenberg’s movable type printing, which is often regarded as the most important invention of the second millennium
Printing press from 1811, photographed in Munich, Germany
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Important years of printing
105AD: Invention of paper by Chinese 868AD: “Diamond Sutra”, the earliest 1st printed book by Chinese 1450: Johann Gutenberg’s invention of movable type. 1789: Lithography invented by Alois Senefelder. 1867: Typewriter was patent. 1887: Monotype was invented by Tolbert Lanston. 1871: Richard Leach developed gelatinebromide dry plate. 1870: George Eastman experimented with gelatine emulsion. 1874: George Eastman patented machine for coating dry plate. 1914: Automated platen. 1954: Introduction of photo setters. 1962: Offset as main printing method. 1973: Introduction of video setters. 1977: Linotype introduction. 1978: monotype introduction. 1985: Adobe developed Post script description language. The RIP( raster image processer) was born and pages started to be assembled with desktop computers. 1991: Introduction of computer to plate. 1993: Short run colour printing. 1995: Touch screen press control. 2000: Digital work flow.
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Printing in India
Classification of printing
Printing came to India as an accident, the ruler of Abbesiana has asked for printing technology from Portuguese. The machinery was being transported along with two technicians. At Goa, one of them died and thus the technology remained in India.
Conventional printing: It is commonly used for mass production. Multiple copies are produced from the master copy from which the print is taken. Each copy remains same and as the number of copies increases, the cost per copy decreases. Non conventional printing: It is used for short run copies. Here no master copy is required because each copy is not same. Each copy is printed in a new form and is different and cost per copy remains the same.
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There are 4 types of conventional printing:
Letter press/ Flexography printing Gravure printing/ Intaglio Screen printing process Lithography/ Planography/ offset
Letter press/ Flexography printing It is the modified version of letter press where sheets used to prepare master are made up of rubber and nylon where as originally they were made of metal sheets. Flexographic presses are capable of producing good quality impressions on many different substrates and is the least expensive and simplest of the printing processes used for decorating and packaging printing.
Gravure printing/ Intaglio process is a printing process in which ink is directly applied to the paper. High volatile inks are used in this printing process. Gravure is an industrial printing process mainly used for the high-speed production of large print magazines and runs at a constant and top quality, such as in the printing of large numbers of magazines and mail order catalogues. Other uses for the gravure processes are in wallpaper and laminate for furniture where quality and consistency are desired. [5]
Screen printing process consists of fine mesh in which non printing area of the mesh are blocked by a coating. The screen plate is covered with ink and a squeegee is passed over it. The process is arguably the most versatile of all printing processes. It can be used to print on a wide variety of substrates, including paper, paperboard, plastics, glass, metals, fabrics, and many other materials. Including paper, plastics, glass, metals, nylon and cotton. Some common products from the screen printing industry include posters, labels, decals, signage, and all types of textiles and electronic circuit boards. The advantage of screen printing over other print processes is that the press can print on substrates of any shape, thickness and size.
Lithography/ Planography/ offset printing is an indirect lithographic technology. Printing and non printing areas are at the same plane but with different chemical properties. The printing is of two kinds, offset and dry offset. In dry offset there is slight difference between the printing and the non printing area, where as in offset, water is used to separate the two.
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There are 5 types of non conventional printing:
Thermography Ionography Inkjet Magnetography Xerox
Thermography printing process produces a glossy, raised image by using infrared light. The image is first printed either by letter press or lithography and then an adhesive ink which is coated with a fusible resin (powder sticks to the wet ink) containing pigment or a metallic powder. When passes under infrared light the resin pigment is fused to give a hard raised image. Thermographic printing refers to two types of printing, both of which rely on heat to create the letters or images on a sheet of paper.
Ionography: A process that creates an image with the use of an electron cartridge which creates a negative charge on a nonconductive surface. The nonconductive surface attracts a magnetic toner. A static electric charge is used to draw the toner particles from the drum onto the substrate. A high pressure roller fuses the toner to the substrate. Also known as ion deposition or electron charge deposition printing. [7]
Inkjet is the digital printing process. It is commonly used for short run copies in which inks are thrown on the paper and passed through the heater which dries the ink, but the process is very quick.
Magnetography: A non-impact printing technique whereby an image is printed using a magnetic toner and magnetic fields on a drum.
Xerox/Electrostatic printing process uses charging and discharging of the drum in the machine where the drum is charged with the positive charge and powder is negative charge. An electrostatic printing process is disclosed wherein a printing roll is formed by forming a latent magnetic image in a magnetic imaging member, decorating the latent magnetic image with a nonconductive magnetic toner to form a toner image, transferring the toner image to a conductive member and temporarily fixing the toner image to the conductive member. The toner image on the conductive member is electro statically charged, while the charge is dissipated from the remaining area of the conductive member. [ 81 ]
Offset production system
Film output Computer to plate Computer to press Computer to paper Prepress: includes all the steps which are carried out before the actual printing. The master copy is prepared in prepress process. Press: the actual printing takes place after the placement of the master on the machine. Post press: includes all those steps which are carried out after printing on paper or another material. Line art: images containing only black and white pixels and are also known as bi-level images. Continuous tone: A grey scale or colour image format capable of illustrating continuously varying tonal ranges as opposite to line art. Soft picture: It is the picture in which the difference between the black and white is very soft. Normal contrast picture: Contains good amount of details. [9]
Other terminologies
Glossy print: Reflection from the images is even so scanning is better. Half tone: It is the process by which continuous tone is stimulated by a pattern of dots of varying sizes by a contact or a glass halftone screen. Halftone screen: It is a sheet of glass or film which breaks the different grey tones of the original into the series of different sizes of dots which gives illusion of continuous tone. Density: It is the measure of tonal values of the original or printed image, and is measured by a densitometer. Density range: The density range of a photographic image is the difference between the highest and the lowest density in that image. It may be referred to as the contrast range. Densitometer: A densitometer is an electric unit that permits to measure grey value and to convert in a figure which we call density.
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Inks and Colours
Colour colour is the visual perceptual property corresponding in humans to the categories called red, yellow, blue and others. Color derives from the spectrum of light (distribution of light energy versus wavelength) interacting in the eye with the spectral sensitivities of the light receptors. Color categories and physical specifications of color are also associated with objects, materials, light sources, etc., based on their physical properties such as light absorption, reflection, or emission spectra.
Inks An ink is a liquid containing various pigments and/or dyes used for coloring a surface to produce an image, text, or design
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Colour gamut and ranges
Refers to the range of colours that can be viewed, displayed or printed. Different colour gamut: Human eye Photographic film Computer monitor Digital printing Offset printing
Hexachrome gamut
Hexochrome gamut: It provides wider colour gamut and was introduced in 1994. More vibrant colours can be obtained for better outputs but the cost increases.
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Other terminologies related to colour
Fake colours: A one colour reproduction printed one coloured sheet is known as a fake colour. Spot colour: Pre-mix readily available inks are called spot colours. These colours can be specified from a colour matching system or hand mixed to match a colour submitted by the designer. These are solid colours. Process colours: The term process colours refer to the use of four specific colours which are cyan, magenta, yellow and black. Colour separation: The prepress changes the original image into four or more films on printing plate. This is called separation. Each film or plate represents separate colours.
Colour correction for prepress:
The quality of the original image. The quality of the scanned image. Ensuring the proper contrast from light to dark. Avoiding the light areas dropping within the photographs.
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Terminologies related to inks
Modifiers Changes the properties of the ink so that it can be used properly for different types of print process and applications. Driers Speeds up the ink drying process. Distillates Improves the flow of the ink. Anti skinning agent Keeps the ink safe from drying too rapidly. Extenders Increases the coverage of the pigment in the ink. Waxes Reduces the possibility of ink from front of one sheet transferring to the back of another. The wax increases the resistance of the wax
Foil stamping
Foil stamping is the application of metallic foil, often gold or silver, but can also be various patterns which are a flat opaque color or white special film-backed 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.
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Binding and terms related
A general term for any of various methods of securing the loose pages or sections of a book or booklet, binding is usually accomplished using stitching, staples, wire, plastic, tape, or glue. The use of ring binding, and saddlestitching with staples are common binding methods for desktop printed documents. Other types of binding such as thermal binding, perfect binding, and case binding are typically done as part of the commercial printing process.
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Different types of binding
Stationary: This consists of wire stitch, office stationary, loose leaf, which are further divided into sub groups. Wire stitch consists of centre stitch and side stitch. Office stationary consists of pads and board binding. Loose leaf consists of flexible binding, spiral binding and ledger. Library: This category consists of soft cover and hard cover which are further sub categorised into following: Hard cover consists of quarter binding, half binding and full binding and full binding is still further divided into flat back, round back, folding, gluing, rounding, backing, head band pasting, case making and linear pasting.
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Imposition
Imposition, in prepress means the arrangement of pages on the press sheet so that when folded the pages read consecutively. How you arrange the pages on the sheet depends upon sizes of the prepress sheet and the pages, and how the job will be folded and bounded. Left to right flip in turning the paperwork and turn. 3mm is the minimum bleed. The type of imposition depends upon various factors The design of the printed piece: whether it is multicolour process, whether one or both sides of sheet are to be printed, whether one or several duplicate images are to be reproduced on the same sheet, and the type of finishing operations that are such as trimming, folding, binding. The type and size of the press to be used, whether the press is sheet fed and if the job is ganged, the size of the press sheet and whether to use a large sheet or a single unit. The type of paper to be used during printing.
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Types of imposition
One side imposition One printing plate is used to print on one side of the sheet as it passes through the printing press. It is used in small offset areas. Sheet wise Sheet wise two printing plates are used. One printing 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.
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Paper in printing
There are two standards in which paper is available
Paper is a thin material mainly used for writing upon, printing upon or for packaging. It is produced by pressing together moist fibers, typically cellulose pulp derived from wood, rags or grasses, and drying them into flexible sheets. British standards International standards British standards: In India still British standard papers are used and there dimensions are as following Full scape: 13.5”by 17” Demy: 17.5” by 22.5” Medium: 18” by 23” Royal: 20” by 25” Crown: 15” by 20” Imperial: 22” by 30” Characteristics of paper Flatness Dimensional stability Proper relative humidity Minimum curling tendency Freedom from active chemicals Free from dust Optical properties Ph value of the paper.
International paper sizes.
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Different types of paper
News print is low cost, low quality, non archival paper and made by mechanical milling process. Wove paper is a writing paper with a uniform surface which is used in text books, bills and records. Bond paper is a high quality durable writing paper, having weight not more than 50grams per meter square. Tracing paper is translucent and resistant to oil, grease and water. Offset paper is rough surface on both sides and good for folding. Duplex board is box board used in cartons. Cartridge paper is the most expensive, more rag content, preserved for long time and is used in certificates and stamp paper. Chromo paper is one side coated. Art paper is china clay coated paper, gives smooth finish, absorbs less ink and can be matt or glossy. Mirror paper is clay coated paper and is thick and used for cards.
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Case study
NID poster 2001-2002 Name of the job: admission posters. Number of colours: 2 colours on one side. Finished size: 11 inches by 22 inches Quantity: 4000 copies + 100 (wasted during the process) Paper: Ballarpur offset paper 23 inches by 36 inches x 26.6 kg (weight of 500 sheets =1 ream) Unfinished size: 12 inches by 23 inches 3 posters from 1 sheet: 4100/3 = 1366 sheets 1400 sheets/500 sheets per ream = 2.8 reams Paper/26.6 kg/Rs 50 per kg = Rs 1350 per ream x 2.8 reams = Rs 3800 (A) Positive: 11 inches x 22 inches = 29 cm x 57 cm = 1653 cm per square. 1653 x Rs 0.75 per square cm = Rs 1240 for positive (B)
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Plate making: 2 colours = 2 plates x Rs 600 per plate = Rs 1200 (C) Printing: 2 plates x 4000 x Rs 900 per plate = Rs 7200 (D) Cutting, finishing, folding: Rs 1000 (E) A + B + C + D + E = 14440 + 10% printers margin = 1444 = 15884 Rs 15884/4000 = Rs 3.97 per copy.
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SOURSES OF INFORMATION
Practical printing and binding Hand book of print media Graphic art manual Introduction to prepress Printing technologies Book binding
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