THEPRI NTHAN DBOOK
12345 Finishes
Print Techniques
Stock
Format
Document Set-up
Colour Modes
Print Processes
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P R I N T P R O C E S S E S
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ffset lithography is a printing technique which is widely used around the world. Most books, newspapers, and magazines are printed using offset lithography, and this printing technique is widely regarded as the workhorse of printing, because it is fast, efficient, cheap, and relatively easy. The “offset� in the name refers to the fact that the ink is transferred to a separate surface before being applied to the paper. The first step in offset lithography is making a plate with the image to be printed. If the image is in black and white, only a single plate is required, because the plate can simply be inked with black ink. Color images are produced using a four-color separation process, in which four different plates are made for the cyan, magenta, yellow, and key (black) inks; when the plates are printed, the colors blend together visually, creating a color image. Plates in offset lithography are entirely flat, in contrast with the textured surfaces of engraved plates and movable type.
L I T H O G R A P H Y A
B G C F
E D
A
Ink Rollers
D
Impression Cylinder
F
Water
B
Plate Cylinder
E
Stock
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Water Rollers
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Blanket Cylinder
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otogravure, a printing process that involves engraving the image onto an image carrier. In gravure printing, the image is engraved onto a cylinder becauseit uses a rotary printing press. Once a staple of newspaper photo features, the rotogravure process is still used for commercial printing of magazines, postcards, and cardboard product packaging. The layout of a gravure printing press follows an in-line arrangement where the required number of printing units is installed along a horizontal plane. In a conventional gravure printing press, each unit comprises of a gravure cylinder which is engraved with the mage to be printed, a doctor blade that removes excess ink, the impression cylinder which presses the stock into the gravure cylinder and finally the ink fountain. The process offers the ability to transfer ink consistently, across a wide range of densities, and at high speeds and the durability of the printing cylinders makes gravure printing an ideal process for providing high quality print on very long or regularly repeating runs, delivering cost advantages over other processes.
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B
C D
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Impression Cylinder
C
Ink Fountain
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Gravure Cylinder
D
Doctor Blade
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Stock
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lexography, a form of rotary printing in which ink is applied to various surfaces by means of flexible rubber (or other elastomeric) printing plates. The inks used in flexography dry quickly by evaporation and are safe for use on wrappers that come directly in contact with foods. In flexography, the desired imagery or lettering is engraved in the form of tiny indentations, or cells, onto a flexible rubber plate by means of plastic-molding techniques. Liquid ink is flooded onto a rotating ink-metering roller while a blade inclined at a reverse angle to the direction of rotation shaves any surplus ink from the ink-metering roller. The remaining ink is rolled onto the rubber plate, which is affixed to a rotary letterpress cylinder, and the plate’s tiny indentations receive and hold the ink. The inked plate then transfers the image or type to the stock that is held on an impression cylinder.
F L E X O G R A P H Y
A F E
B
D
C
A
Impression Cylinder
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Ink Fountain
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Doctor Blade
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Plate Cylinder
D
Anilox Roller
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Stock
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ad printing is a printing process that can transfer a 2-D image onto a 3-D object. This is accomplished using an indirect offset (gravure) printing process that involves an image being transferred from the clichĂŠ via a silicone pad onto a substrate. Pad printing is used for printing on otherwise impossible products in many industries including medical, automotive, promotional, apparel, and electronic objects, as well as appliances, sports equipment and toys. It can also be used to deposit functional materials such as conductive inks, adhesives, dyes and lubricants. Physical changes within the ink film both on the clichĂŠ and on the pad allow it to leave the etched image area in favor of adhering to the pad, and to subsequently release from the pad in favor of adhering to the substrate. The unique properties of the silicone pad enable it to pick the image up from a flat plane and transfer it to a variety of surfaces, such as flat, cylindrical, spherical, compound angles, textures, concave, or convex surfaces.
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P R I N T I N G
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B
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Pad
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Ink
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Product
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creen printing is a printing technique that uses a woven mesh to support an ink blocking stencil. The attached stencil forms open areas of mesh that transfer ink or other printable materials which can be pressed through the mesh as a sharp-edged image onto a substrate. A fill blade or squeegee is moved across the screen stencil, forcing or pumping ink into the mesh openings for transfer by capillary action during the squeegee stroke. Screen printing is also a stencil method of print making in which a design is imposed on a screen of polyester or other fine mesh, with blank areas coated with an impermeable substance, and ink is forced into the mesh openings of the mesh by the fill blade or squeegee and onto the printing surface during the squeegee stroke. It is also known as silkscreen, serigraphy, and serigraph printing. A number of screens can be used to produce a multicoloured image.
S C R E E N
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D
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Ink
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Squeege
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Frame
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Stock
C O L O U R
M O D E S
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he CMYK colour model is a subtractive colour model, used in color printing, and is also used to describe the printing process itself. CMYK refers to the four inks used in some colour printing: cyan, magenta, yellow, and key (black). Though it varies by print house, press operator, press manufacturer, and press run, ink is typically applied in the order of the abbreviation. The “K” in CMYK stands for key since in four-colour printing the printing plates are carefully keyed or aligned with the key of the black key plate. Some sources suggest that the “K” in CMYK comes from the last letter in “black” and was chosen because B already means blue. The CMYK model works by masking colours on a lighter background. The ink reduces the light that would be reflected. Such a model is called subtractive because inks “subtract” brightness from white. With CMYK printing, halftoning allows for less than full saturation of the primary colors; tiny dots of each primary colour are printed in a pattern small enough that human beings perceive a solid color.
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he RGB colour model is an additive coloir model in which red, green, and blue light are added together to reproduce a broad array of colours. The name of the model comes from the initials of the three additive primary colours, red, green, and blue. The main purpose of the RGB colour model is for the sensing, representation, and display of images in electronic systems, such as televisions and computers, though it has also been used in conventional photography. The RGB colour model is additive in the sense that the three light beams are added together to make the final colour’s spectrum. Zero intensity for each component gives the darkest color (no light, considered the black), and full intensity of each gives a white. When the intensities for all the components are the same, the result is a shade of gray, darker or lighter depending on the intensity. When the intensities are different, the result is a colorized hue, more or less saturated depending on the difference of the strongest and weakest of the intensities of the primary colours employed.
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H E X A C H R O M E
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exachrome is a six colour printing process designed by Pantone Inc. In addition to custom CMYK inks, Hexachrome added orange and green inks to expand the color gamut, for better color reproduction. It was therefore also known as a CMYKOG process.
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he Pantone ColourMatching System is largely a standardised colour reproduction system. It allows different manufacturers in different locations to refer to the system and make sure colours match without direct contact with one another. It also allows you to use colours that cannot be mixed in CMYK. Pantone offers books so you can see what the colour would look like on coated, uncoated and matte stocks. The colours are distinguished by a number and a suffix, the number is the colour and the suffix the stock.
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S P O T C O L O U R
spot colour is an ink that is ready mixed to produce a particular colour. The standard reference for spot colour in the UK is Pantone. The more spot colours used the more plates are needed, increasing the cost. To reduce costs ‘tints’ of a spot colour can be used.
D O C U M E N T S E T U P
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REGISTRATION In colour printing registration is the method of correlating overlapping colours on a single image and the alignment of specific marks. When printing an image that has more than one colour, with certain methods of printing, it is necessary to print separate colour runs. So if each of the colours line up correctly, the registration will form a completed and aligned mark.
C R O P M A R K S Crop marks add fine horizontal and vertical rules that define where the page should be trimmed to remove the excess from the print. Crop marks also help register (align) one colour separation to another. Crop marks are typically used when printing to a larger sheet of paper than the final trim size of the document, especially when using bleeds to ensure a precise trim.
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Bleed marks add fine rules that define the amount of extra area to an image outside the defined page size. When any image or element on a page touches or extends beyond the trim edge, leaving no margin it is said to bleed. Elements that bleed off the page can sometimes add to the cost of printing if the printer must use a larger size of paper to accommodate the bleed allowance.
C O L O U R B A RS Colour bars add small squares of colour representing the CMYK inks and tints of grey (in 10% increments). They’re printed outside the trim area and are used for quality control purposes by the printer. They are used by proofers and press operators to control the trapping, ink density, dot gain, and print contrast of the proof or the printed sheet. They are a reference point.
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SIZE
H x W (MM)
SIZE
H x W (MM)
A0
1189 x 841
B0
1414 x 1000
A1
841 x 594
B1
1000 x 707
A2
594 x 420
B2
707 x 500
A3
420 x 297
B3
500 x 353
A4
297 x 210
B4
353 x 250
A5
210 x 148
B5
250 x 176
The ISO paper size standard is based on each size being half of the size of the previous one, when folded parallel to the shorter lengths. This system allows for a variety of useful applications, such as the enlarging and reducing of images without any cutoff or margins, or folding to make a booklet of the next size down. The mathematics behind this useful feature is that the sheets have an aspect ratio (that’s the ratio of the length to the width) of the square root of 2.
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E N V E L O P E S
C6 C4
C5
C envelopes sizes are defined as the geometric mean of the A and B sizes with the same number i.e. C4 dimensions are the geometric mean of A4 and B4. This produces a size between the two that makes an envelope that will neatly hold the A series paper of the same size, thus a C4 envelope is perfect for an A4 sheet of paper unfolded. It should be noted that C format envelopes also have an aspect ratio of 1:root2 because of this an A4 sheet folded parallel to its shortest sides will fit in a C5 envelope and folded twice will fit a C6 envelope.
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The RA and SRA paper formats are defined by ISO 217 “Paper - Untrimmed Sizes” and cover untrimmed raw paper for commercial printing. The RA and SRA sizes are slightly larger than the corresponding A series sizes to allow for bleed on printed material that will be later trimmed to size, often for bound publication.
SIZE
H x W (MM)
SIZE
H x W (MM)
RA0
1220 x 860
SRA0
1280 x 900
RA1
860 x 610
SRA1
900 x 640
RA2
610 x 430
SRA2
640 x 450
RA3
430 x 305
SRA3
450 x 320
RA4
305 x 215
SRA4
320 x 225
RA stands for “raw format A”
SRA stands for “supplementary raw format A”
105% of the A series size
115% of the A series size
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North America, including the US, Canada and parts of Mexico, is the only area of the first world that doesn’t use the ISO 216 standard paper sizes, instead they use Letter, Legal, Junior Legal and Ledger/Tabloid paper sizes and those that have been formalised in ANSI Y14.1M - Metric Drawing Sheet Size & Format.
SIZE
W x H (MM)
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Letter
216 x 279
B
Legal
216 x 356
C
Junior Legal
127 x 203
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Ledger / Tabloid
279 x 432
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TABLOID: The word tabloid when referring to newspaper sizes comes from the style of journalism known as ‘tabloid journalism’ that compacted stories into short, easy to read and often exaggerated forms. The tabloid size is widely used across the globe these days and r ecently many established papers have changed from broadsheet size to tabloid size as it has proved more popular with readers. COMPACT: This size is the same as tabloid. The term being coined when the ‘quality’ or ‘high brow’ press titles moved from the traditional broadsheet size to the smaller tabloid size, as they didn’t want to be associated with the sensationalism of tabloid journalism.
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BROADSHEET: The term broadsheet derives from single sheets of political satire and ballads sold on the streets, which became popular after the British placed a tax on newspapers by the number of pages in 1712. The broadsheet size for newspapers is becoming less popular and many titles are switching from broadsheet to tabloid. In Australia and New Zealand the term broadsheet is used to refer to papers that are printed on A1 size paper. BERLINER: The Berliner format (also known as Midi) is commonly used by newspapers across Europe. Confusingly the title ‘Berliner Zeitung’, often referred to as just ‘Berliner’ is not printed in berliner size.
SIZE
W x H (MM)
A
Tabloid / Compact
430 x 280
B
Broadsheet
750 x 600
C
Berliner
470 x 315
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W E I G H T
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( G S M )
eight is the thickness of paper. There are two conventions currently used for paper weights gsm (grams per square meter) and basis weight. Gsm is used in europe and places that use ISO paper sizes. This standard defines grammage as grammes per square meter (g/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 ISO 216 as having an area of 1 square meter. An A0 sheet of 80gsm paper will weigh 80 grams, an A0 sheet of 100gsm paper will weigh 100 grams. Paper used in offices is usually between 70gsm and 80gsm. With 80gsm being the most popular. Above 120gsm come various thicknesses of card. Newspaper ranges between 45gsm and 50gsm.
COATED PAPER: Coating is a process by which paper or board is coated with an agent to improve brightness or printing properties. By applying PCC, china clay, pigment or adhesive the coating fills the miniscule pits between the fibres in the base paper, giving it a smooth, flat surface which can improve the opacity, lustre and colour-absorption ability. Various blades and rollers ensure the uniform application of the coating. Available in gloss, satin and matte. UNCOATED PAPER: Not all paper is coated. Uncoated paper is typically used for letterheads, copy paper, or printing paper. Most types of uncoated paper are surface sized to improve their strength. Such paper
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is used in stationary and lower quality leaflets and brochures. It is generally more absorbent than coated paper. WOVE: Paper made on a closely woven wire roller or mold and having a faint mesh pattern. Popular for stationary and book publishing. It has a uniform surface not textured like laid paper. LAID: Premium quality paper with a textured pattern of parallel lines, similar to hand made paper. Commonly used for business stationary. BOND: A high quality durable paper, often used for copying or laser printers. A higher bond stock that can be used for letterheads.
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PRINT TECHNIQUES
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mbossing and debossing are processes of pressing paper into relief using heat and force. Each of these processes are different and create a different end result. Embossing applies pressure to the back of the stock to create a raised three dimensional effect. Whereas, debossing has the pressure applied to the front creating an indented look by pushing the material down. Two metal dies are used for this procedure, a raised and a recessed (male/female). The raised die forces the stock into the recessed/counter die to create the impression. In impressing an embossed image through a surface, the image has to be 3 times thicker than the material it’s being pushed through. ‘Blind embossing’ means that no foiling or printing is required and ‘foil embossing’ is where foil is used in the process. Embossing on heavier stocks will most often provide greater dimensional depth and detail and long fiber sheets are the best sheets to emboss because they can handle a wide variety of embossing dies. Coated, varnish or lightweight stocks may have a tendency to crack when embossed. Emboss with the grain of the paper to minimize cracking.
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Female Die
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Stock
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Male Die
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oil stamping is a specialty printing process that uses heat, pressure, metal dies and foil film. The foil comes in rolls in a wide assortment of colours, finishes, and optical effects. Foil stamping is similar to letterpress and engraving, in that the colour is applied to paper with pressure. As a result, the foil process leaves a slightly raised impression on the paper. Once the design is finalised, metal dies are created in the appropriate shape for each color foil to be applied, and for embossing if a three-dimensional effect is desired, this is commonly known as blind embossing. The dies are heated and then stamped with enough pressure to seal a thin layer of foil to the paper. Foil is an opaque medium and unlike most processes doesn’t use any ink. As a result, the foil colour does not change based on the colour of paper on which you are printing. This makes metallic or lighter colour foil great for darker or colored papers. Foil can be used for a variety of finishes, including metallic, matte, glossy, pearlescent and patterns such as marbling. There are also semi-transparent tint foils, if you do want to allow the paper color to show through.
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Press
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Die
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Foil
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Heater
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Foil Holder
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Foil Puller
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arnish is basically clear ink and can be gloss satin or matte. A flood varnish covers the entire printed page for protection or sheen. A spot varnish allows you to highlight specific areas of a printed space and adds shine and depth to specific elements on the page such as logo or image. Varnishes are also applied on press, but they are heavier bodied and can be applied (like inks) to certain areas (spot varnish). A plate must be created to apply a spot varnish, so artwork is necessary. There is also UV varnishes, the UV stands for ultra violet, the way it is dried. They are available glossy and also mattes and tints.
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C U T T I N G
ie cutting is a process in manufacturing that cuts uniform shapes from paper, wood, metal and cloth. Die cut machines may be large for industrial purposes, or smaller and less expensive for use by individuals. The die itself is often a blade that has been bent into the desired shape. The blade is secured to a backing and inserted into the machine. When in operation, the die functions much like a cookie cutter, pressing shapes from the material rolling through the machine. Die cut machines may be manually operated or computerised. Industrial-sized die cut machines are made to produce at high volumes and fast speeds. For industrial purposes, die machines can be used to do different tasks, such as bending and trimming, in addition to cutting. Each operation requires a different kind of die. Products produced by dies include keys, kitchen utensils, car parts, buttons, paper products and aluminum cans.
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SADDLE STITCH: Signatures are nested (set one into the other rather than stacked) and then stitched through the fold with staples made of thin wire. These books can lie flat. However, saddle stitching only works for shorter books of up to 80 pages or so. These books also have no spine on which to print a title.
PERFECT BOUND: Perfect bound books are made up of stacked signatures. These are gathered into a book and glued into a paper cover. Without reinforced endsheets or a binders board cover material, perfect bound books are less durable than case bound books but are significantly cheaper.
CASE BOUND: This method is what is called a hardcover book. It is the most expensive option but the most durable. Stacked signatures are gathered and sewn together for strength. This book block is trimmed on three sides and then glued into a spine, front cover, and back cover (a single unit) made of binders board.
SIDE STITCH: Side stitched books are loose sheets of paper stapled together. A paper cover can be wrapped around the entire stack and glued to form a printable spine. However, side-stitched books do not lie flat. This is a popular method for calendars and note pads where a perforation is often added to allow tear-off.
LAY FLAT BOUND: Perfect bound books do not lie flat when opened because the spines are fully glued to the cover. By using a flexible glue on only the edges of the spine, perfect bound publications can be made to lie flat on a table. This method is more expensive than perfect binding and requires more time for the glue to cure.
SPIRAL BOUND: After being punched with small holes down the spine, a coiled spiral binding is screwed through the holes. Documents bound with a spiral can open flat on a desk or table and offer 360 degree rotation for easy note taking. They are also available in more colors and sizes than other binding styles.
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Saddle Stitch
C
Case Bound
E
Lay Flat Bound
B
Perfect Bound
D
Side Stitch
F
Spiral Bound
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4 Page Fly
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8 Page Roll
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8 Page Short
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6 Page Roll
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8 Page French
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8 Page Gate
C
6 Page Concertina
G 8 Page Map
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10 Page Concertina
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8 Page Parallel
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Perfect Bound
8 Page Concertina
B I B L I O G R A P H Y
wisegeek.com offsetprintingtechnology.com wikipedia bobst.com castleprint.co.uk help.adobe.com about.com webmartuk.com npes.in www.benwells.co.uk www.paperrep.com ohsobeautifulpaper.com printingforless.com ehow.com printindustry.com deltaleeds.co.uk
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