/ Print guide
/ A ‘‘Top Ten Manual’ focusing on the main aspects of commercial print processes and the know how to getting it right in print.
/ OUGD201 Design Production - Print What is Design for Print? Baljeet Kaur Samra
/ Contents 1 / Paper Size A/B/C Standarised Paper sizes
7 / Trapping The importance of ensuring that trapping has been considered in your work.
2 / Printing Methods Lithography Flexography Screen Printing Digital
8 / Print Finishes Varnishes Embossing / Debossing Foil Blocking
3 / Colour CMYK & RGB PMS Spot Colours Duotone Tints / Shades / Tones
9 / Proofing The importance of proofing your work before having it printed.
4 / Stock
5 / Imposition
6 / File types
A guide to different stock and their primary uses.
A guide to imposition when send artwork to print.
Which file types to use when sending your artwork to print.
10 / Costings Choosing the right printer and getting you’re constings right.
/ Paper size ‘A’ Series
‘B’ Series
‘C’ Series
AO A1 A2 A3 A4 A5 A6 A7 A8 A9 A10
AO A1 A2 A3 A4 A5 A6 A7 A8 A9 A10
AO A1 A2 A3 A4 A5 A6 A7 A8 A9 A10
841 x 1189 594 x 841 420 x 594 297 x 420 210 x 197 148 x 210 105 x 148 74 x 105 52 x 74 37 x 52 26 x 37
1000 × 1414594 707 × 1000 500 × 707 353 × 500 250 × 353 176 × 250 125 × 176 88 × 125 62 × 88 44 × 62 31 × 44
917 × 1297 648 × 917 458 × 648 324 × 458 229 × 324 162 × 229 114 × 162 81 × 114 57 × 81 40 × 57 28 × 40
ISO Paper Size The ISO paper size system is an international standard that is used in many places in the world in copy and print devices that defines paper sizes. Based on the metric system, the ISO paper size system uses a height-to-width ratio with an aspect ratio of 1 to 1.414, If a sheet is cut into two, the resulting halves are the same proportions as the original.
/ printing methods Lithography
Flexography
Screen Printing
In modern lithography, the image is made of a polymer coating applied to a flexible aluminum plate. To print an image lithographically, the flat surface of the stone plate is roughened slightly etched and divided into regions that accept a film of water, and thereby repel the greasy ink. The image can be printed directly from the stone plate (the orientation of the image is reversed), or it can be offset, by transferring the image onto a flexible sheet (rubber) for printing and publication.
Flexography (often abbreviated to flexo) is a form of printing process which utilises a flexible relief plate. It is basically an updated version of letterpress that can be used for printing on almost any type of substrate including plastic, metallic films, cellophane, and paper. It is widely used for printing on the non-porous substrates required for various types of food packaging.
Screen 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. A roller or squeegee is moved across the screen stencil, forcing or pumping ink past the threads of the woven mesh in the open areas.
Digital Printing Digital printing refers to methods of printing from a digital based image directly to a variety of media. Refers to professional printing where small run jobs from desktop publishing and other digital sources are printed using large format and/or high volume laser or inkjet printers. It also allows for on demand printing, short turn around.
Commercial Printing Processes Explaining the process behind various printing techniques such as; Lithography Flexography Screen printing Digital printing
/ Litho Printing How does Litho printng work?
using a machine that exposes the plate, using lasers directly from the computer. Both of these ways create a The process of Litho Printing photographic negative of the is based on the basic principle image/text for print, releasing that oil and water do not mix. the emulsion, and transferring The first step begins with the a clear image to the emulsion. plates. Lithographic plates have The final step is very similar a roughened surface and are to developing film in a photo coated with a photosensitive lab. The emulsion is then (light sensitive) emulsion. This emulsion is a suspension of two chemically treated to remove chemicals that cannot be mixed the unexposed portions. Once the printing plate together. has been made, the printing There are two ways that the image/text is rendered grease plates are made : 1 - Exposure from light source receptive and hydrophobic, or water repelling. with film on top of the plate. On the press the plate is then 2 – Exposure to the plate mounted on the plate cylinder
which as it rotates, will come into contact with the wet rollers by a dampening solution or water, adhering to the rough or negative portions of the image. Then the plate will come into contact with the roller coated with ink, and this will then adhere to the smooth or positive portions of the image. If this image were to be transferred directly to paper, it would create a positive image, but there would be moistened paper. To prevent this, a cylinder covered with a rubber surface, known as a blanket, is rolled over the plate. The blanket squeezes away the water, and picks up the
ink. The cylinder is then rolled over the paper, transferring the ink. This is called “offset lithography� because the image is first transferred to the blanket cylinder, and the image is offset to the drum before being applied to the paper.
/ Flexo Printing How does Flexo printng work?
platemaking involves establishing the wanted image in a digital format (typically with a desktop publishing program) Flexographic printing and using that digital master begins with development of a flexographic plate. Flexographic image to laser-etch the plate. The final method is to create plates can be created using a mold. In this technique, a three different methods. One metal plate is exposed using method uses a UV reactive a negative. Following the polymer. UV light is shined onto a film negative positioned exposure, the plate is given an acid bath creating an engraved over the polymer. The polymer image. A master plate mold is reacts to the UV that comes produced from the engraved through the negative and metal plate, and the final hardens. The unhardened polymer is removed using water printing plate is produced from the master mold. or a chemical solvent. Effectively, there are three A second technique is rollers involved: a meter roll (so digital platemaking. Digital
called because it meters the amount of ink applied to the plate), a roller with the plate attached, and a impression roller. The meter roll applies a predetermined measurement of ink to the plate. The plate is subsequently scraped by the doctor blade. The substrate is passed between the print plate and the impression roller, which applies pressure to the keep the substrate against the plate.
/ Screen Printing How does Screen printng work? The equivalent of the printing plate for the screen printer is the screen - a wooden or aluminium frame with a fine nylon mesh stretched over it. The mesh is coated with a light sensitive emulsion or film, which - when dry - will block the holes in the mesh. The image that needs to be printed is output to film either by camera or image-setter. This film positive and the mesh on the screen are sandwiched together and exposed to ultra-violet light in a device
called a print-down frame. The screen is then washed with a jet of water which washes away all the light sensitive emulsion that has not been hardened by the ultra-violet light. This leaves you with an open stencil which corresponds exactly to the image that was supplied on the film. Now the screen is fitted on the press and is hinged so it can be raised and lowered. The substrate to be printed is placed in position under the screen and ink is placed on the top side of the screen, (the frame acts also as wall to contain the ink ). A rubber blade gripped in a wooden or
metal handle called a squeegee (not unlike a giant wind-screen wiper) is pulled across the top of the screen; it pushes the ink through the mesh onto the surface of the substrate you are printing. To repeat the process the squeegee floods the screen again with a return stroke before printing the next impression.
/ Digital Printing How does Digital printng work? Digital Printing takes a different approach assembling each image from a complex set numbers and mathematical formulas. These images are captured from a matrix of dots, generally called pixels, this process is called digitizing. The digitized image is then used to digitally controlled deposition of ink, toner or exposure to electromagnetic energy, such as light, to reproduce images. The mathematical formulas also allow for algorithms to compress the data. It also give
a method of Calibration or Color Management Systems which helps to keep images looking the same color despite where they are view or printed. One important function that the mathematical formulas allowed was the development of a common language for digital printing it is called PostScript and was developed by Adobe. To see what PostScript looks like open a PDF or EPS in a text editor, the code seems very intricate but to a computer it just a simple code of instructions. One of the most important advantages that Digital printing
offers is a quicker response time due to its minimal press setup and it’s built in multicolor registration system. This eliminates many of the upfront, time consuming processes that can cause analog printing methods to have a slower turnaround time. Another advantage of Digital printing is the ability of offer variable printing; this means that each printed piece can have different information on it providing personalization and customization unmatched by analog processes.
/ Colour CMYK & RGB
Pantone Matching
Spot Colours
The CMYK color model is a subtractive color model, used in color printing. CMYK refers to the four inks used in some color printing: cyan, magenta, yellow, and key (black). The RGB color model is an additive color model in which red, green, and blue light is added together in various ways to reproduce a broad array of colors. Name of the model comes from the initials of the three additive primary colors, red, green, and blue. The main purpose of the RGB color model is for the sensing, representation, and display of images in electronic systems, such as televisions and computers.
A popular color matching system used by the printing industry to print spot colors. Most applications that support color printing allow you to specify colors by indicating the Pantone name or number. This assures that you get the right color when the file is printed, even though the color may not look right when displayed on your monitor. PMS works well for spot colors but not for process colors, which are generally specified using the CMYK color model.
In offset printing, a spot color is any color generated by an ink (pure or mixed) that is printed using a single run. The widely spread offsetprinting process is composed of four spot colors: Cyan, Magenta, Yellow, and Key (black) commonly referred to as CMYK. More advanced processes involve the use of six spot colors (hexachromatic process), which add Orange and Green to the process (termed CMYKOG). The two additional spot colors are added to compensate for the ineffective reproduction of faint tints using CMYK colors only. The term spot color can also mean any color generated by a non-standard offset ink; such as metallic, fluorescent, spot varnish, or custom hand-mixed inks.
Duotone
Tints / Shades / Tones
Duotone is a halftone reproduction of an image using the superimposition of one contrasting color halftone (traditionally black) over another color halftone. This is most often used to bring out middle tones and highlights of an image. The most common colors used are blue, yellow, browns and reds.
These terms are often used incorrectly, although they describe fairly simple color concepts. If a color is made lighter by adding white, the result is called a tint. If black is added, the darker version is called a shade. And if gray is added, the result is a different tone.
Colour Models & Techniques This section looks at the difference between CMYK & RGB as well as focusing on spot colours, dutotone and tints.
/ Stock Cast Coated High quality Colour Printing
Chromo Labels, Wrapping, Covers
Cartridge Adds Texture
Coated paper with high gloss finish. Wet coated paper is pressed / cast against a hot metal drum.
Waterproof coating on single side intended for good embossing and varnishing performance.
Thich white paper particularly used for pencil and ink drawings.
Newsprint Newspapers & Comics
Antique Adds Texture
Uncoated woodfree Office paper
Made from mechanically ground wood pulp. Cheap to produce.
Roughest finish offered on offset paper.
Printer, photocopy paper, general office use. Largest printing and writing paper category by capacity.
Art Colour printing & Magazines High quality paper with clay filler to give good printing surface.
Greyboard Packaging Material Lined or unlined board made from waste paper.
Types of Stock Stock is an integral part of every print process, here are a few stock choices that are widely available. Print & Finish // Gavin Ambrose, Paul Harris // AVA Publishing
Artboard Cover Stock Uncoated board
/ Imposition How does imposition work? 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. Imposition is affected by five different parameters: Format of the product: The size of the finished page determines how many pages can be printed on a single sheet. Number of pages of
the printed product: The compositor must determine how many sheets are to be printed to create a finished book. Stitching/binding method: The compositor must understand how the sheets are placed to form the signatures that compose the finished book. Paper fiber direction: Many papers have a “grain,� reflecting the alignment of the paper fibers. That these fibers must run lengthwise along the fold influences the alignment,
hence the position, of the pages on the printed sheet. To understand how the pages are related to each other, an imposition dummy may be used. This is made by folding several sheets of paper in the way the press will print and fold the product. A little copy is then created, and this can help paginate the product.
Imposition Imposition is one of the fundamental steps in the prepress printing process. It consists in the arrangement of the printed product’s pages on the printer’s sheet, in order to obtain faster printing, simplified binding and less waste of paper.
/ File types Which files should you send to print? You are best off saving vector artwork (the sort of stuff from Illustrator) as an EPS, PDF or AI file. In this photo from the Print Handbook you can see why PDFs (bottom left) and EPSs trump TIFFs and JPEGs every time for vector stuff. Even at 300dpi the TIFF and JPG don’t handle this vector graphic nearly so well. They have to convert it to pixels, and in this situation it shows. Bitmaps TIFFs, JPEGs and even PSDs are what you should be saving
your bitmap files as (the sort of things created in Photoshop). TIFFs and PSDs are lossless. You don’t lose any quality by saving a file as a TIFF or PSD. JPEGs normally lose quality when you save them but take up a lot less space on your computer. A very high quality JPEG is often not a lot different to a TIFF or PSD, but it does very much depend on the sort of image you’re saving. A TIFF or PSD is normally a better option than a JPEG. But if you’ve been supplied with a
JPEG, from a camera or stock photo website, and you’re not modifying the image then you will gain nothing from saving it as a TIFF or PSD. A TIFF or PSD cannot create detail where there was none in the first place. But a JPEG can remove detail where once there was some. There’s a couple of thing to notice in the pictures here related to JPEGs. Firstly, JPEGs can’t handle spot colours. So when this JPEG was saved it converted the Pantone colour
File Types into a CMYK value. Secondly, the white space in between the red lines on the JPEG is filled with a very subtle yellow/ grey tint. This is due to the compression. Files for your printers: Ask them but probably PDFs or native Creative Suite files (.ai, .psd, .indd) Vectors: EPSs, PDFs and AIs Bitmaps: TIFFs, PSDs and sometimes JPEGs www.printhandbook.com
It is essential when sending files to print, that you have discussed with your printer which type of file they will be using to then print your artwork
/ Trapping Trapping Methods One approach to trapping is to change the submitted artwork. In general, all digital files produced using any current professional software have some level of trapping provided already, via application default values. Additional trapping may also be necessary, but all traps should be as unobtrusive as possible. Traps can be applied at several stages in the digital workflow, using one of two trapping technologies: vectorbased and raster-based. The
right choice will depend on the type of products (packaging applications including flexo-printing have other requirements than commercial printing on offset systems) and the degree of interactivity or automation that is wanted.
Trapping Trapping is a term most commonly used in the prepress industry to describe the compensation for misregistration between printing units on a multicolor press. This misregistration causes unsightly gaps or whitespace on the final printed work. Trapping involves creating overlaps (spreads) or underlaps (chokes) of objects during the print production process to eliminate misregistration on the press.
/ Print Finishes Embossing & Debossing
Spot Varnishes
Foil Blocking
Embossing is the process of creating a three-dimensional image or design in paper and other materials. Embossing is typically accomplished by applying heat and pressure with male and female dies, usually made of copper or brass, that fit together and squeeze the fibers of the substrate. In debossing an image such as a logo, a title, or other design is heat-pressed into the surface of the paper with a die, creating depressions or indentations rather than raised impressions as in embossing.
A varnish is a liquid coating applied to a printed surface (for example the outside of a presentation folder) to add a clear glossy, matte, satin, or neutral finish. Spot Varnish is applied to chosen spots (areas), of a printed piece. This has the affect of highlighting and drawing attention to that part of the design, but it also provides the additional visual stimulus of having varied textures on a single printed surface.
Foil stamping, typically a commercial print process, is the application of pigment or metallic foil, often gold or silver , but can also be various patterns or what is known as pastel foil which is 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. Foil stamping can be combined with embossing to create a more striking 3D image.
Print Finishes Looking at the various print finishes that can be applied to artwork such as; Varnishes Embossing / Debossing Foil Blocking
/ Proofing What is Proofing? The primary goal of ‘proofing’ is to serve as a tool for customer verification that the entire job is accurate. Prepress proofing (also known as off-press proofing) is a cost effective way of providing a visual copy without the expense of creating a Press Proof. If errors are found during the printing process on press it can prove very costly to one or both parties involved. The main objective of proofing is to produce either a soft or hard copy of what the final product will look like on press. Hard copy proofing
usually involves ink-jet printing or other technologies (i.e. Laminate Proof) to produce high-quality one-off copies of the production artwork. Soft proofing usually involves highly color accurate wide-gamut computer displays. In the best conditions the proofing process will actually try to emulate the effects of the printing press through color management and screening techniques, which can be quite challenging because proofing devices may behave and operate quite differently than press devices.
Proofing The primary goal of ‘proofing’ is to serve as a tool for customer verification that the entire job is accurate before it is printed.
/ Costing What is Proofing? Commerical Costings Print costing is an integral part of any print project. Is essential to ensure that you have discussed your exact requirements with your printer so there are no issues about extra costs. It always a good idea to get a quote from 2 or 3 different printers just so that you have an idea of how much it will cost - allowing you to make the decision that best suits you.