Print Guide

The Print Guide:A top ten manual on key considerations within commercial print

1. CMYK (4 seperations) & RGB-2. Converting CMYK to RGB-3. Colour Gamut-4. Paper Stocks-5. Paper Sizes-6. PMS (colour for coated/uncoated etc)-7. Linen Testers-8.Printing Methods-9. Finishing-10. Costs

CMYKCyan, Magenta, Yellow and Key (black)

CMYK is subtractive.

“A subtractive colour model explains the mixing of paints, dyes, inks, and natural col-orants to create a full range of colours, each caused by subtracting (that is, absorbing) some wave lengths of light and reflecting the others.”

RGBRed, Green and blue

RGB is additive

“An additive colour model involves light emit-ted directly from a source or illuminant of some sort. The additive reproduction process usually uses red, green and blue light to produce the other colours.”

CMYK//RGB

Notice the centers of the two colour charts. In the RGB model, the convergence of the three primary additive colours produces white. In the CMYK model, the convergence of the three primary subtractive colours produces black.

In the RGB model notice that the overlap-ping of additive colours results in subtractive colours. In the CMYK model notice that the overlapping of subtractive colours results in additive colours (red, green and blue).

Also notice that the colours in the RGB model are much brighter than the colors in the CMYK model. It is possible to attain a much larger percentage of the visible spec-trum with the RGB model. That is because the RGB model uses transmitted light while the CMYK model uses reflected light.

The muted appearance of the CMYK model demonstrates the limitation of printing inks and the nature of reflected light. The colours in this chart appear muted because they are displayed within their printable gamut.

Cyan Magenta

Yellow Ke

When various tints of the four colours are printed in overlapping patterns it gives the illusion of continuous tones - like a photograph:

CMYK is design for print. The CMYK printing method is also known as “four-colour process” or simply “process” colour. All of the colours in the printable portion of the colour spectrum can be achieved by overlapping “tints” of cyan, magenta, yellow and black inks. A tint is a screen of tiny dots appearing as a percentage of a solid colour.

Converting CMYK to RGB

Converting from rgb to cmyk forces drastic changes in colour. Be careful when printing incorrectly converted files. The RGB model displays a much larger percentage of the vis-ible spectrum than the CMYK model and, as a result, has a wider gamut. Once an image has been converted from RGB to CMYK and brought into printable gamut, the extra RGB data will be lost.

It is important to choose the right colour model for the job. If your images will be printed, then convert them to CMYK and manually bring them into gamut before printing.

Colour Gamut

Each color model has is own gamut (range) of colours that can be displayed or printed. Each color model is limited to only a portion of the visible spectrum. Since a color model has a particular range of available colour or gamut, it is referred to as using a “colour space”. An image or vector graphic is said to use either the RGB color space or the CMYK color space (or the color space of another colour model). Some graphic applications present the user with more than one colour model for image editing or illustration and it is important to choose the right one for the task.

The CMYK model forms its gamut from the primary subtractive colours of cyan, magenta and yellow. When the cmy inks are combined it forms black - in theory. However, because of the impurities in ink, when cmy inks are combined it produces a muddy brown color. Black ink is added to this system to compensate for these impurities.

Paper Stocks & Weights

“When considering a print quotation for a particular project, it is important to make sure the stock selected suits the proposed project.”

Colours will alter upon the stock you choose. Always consider the texture, colour, weight and size of the stock before printing to avoid any nasty surprises. The type of paper will decide your print results. For example, magenta on an uncoated stock will differ to magenta on a coated stock.

The best way to avoid stock issues is to try out samples and experiment with the colour comparisons. Don’t be wary to ask printers for advice and their opinion on your chcoice of stock. Later in the presentation I will go on to talk about how choosing the correct stocks wisely will save costs on print finishing, especially vital when working with a client and working to a limited budget.

When working with clients, it is important to get a quotation. These can be obtained through your printer. A quotation backs up your work and shows the client that the con-cept you have delivered is realistic and within the conversed budget.

Paper Sizes

Sounds simple when spoken about broadly but paper sizes are a tricky subject when it comes to commercial print.

“SRA size paper is used by commerical printing companies. It is slightly larger than the A series to provide room for grip, trim and bleed. These paper series are untrimmed raw paper. RA stands for “raw format A” and SRA stands for “supplementary raw format A”. The RA and SRA formats are slightly larger than the corrsponding A series formats. These paper sheets will after printing and binding be cut to the match the A format.”

The bleed is essential. This is when printing onto an SRA size paper to reach the edges of the sheet. A series formats do not allow edge printing so printing onto an SRA (slightly bigger than an A) gives you the opportunity to design to the edges and trim down to the natural A size format.

A series format and SRA formats that are key to remember:

0 - 841 x 1189mmA1 - 594 x 841mmA2 - 420 x 594mmA3 - 297 x 420mmA4 - 210 x 297mmA5 - 148 x 210mmA6 - 105 x 148mm

SRA0 - 900 x 1280mmSRA1 - 640 x 900mmSRA2 - 450 x 640mmSRA3 - 320 x 450mmSRA4 - 225 x 320mm

It is useful to memorise the sizes so con-versation and debating with printers flows. Printers and future employees also respect the quick knowledge you have of papers and stocks that others fall short on when asked on the spot.

PMS

Earlier in the top ten I mentioned gamuts and stock choices. PMS stands hand in hand with these. Checking colour reproduction through Pantone Swatches define how a col-our will reproduce on a certain surface/stock. I mentionedcoated and uncoated surfaces briefly. They represent different formulations based on what type of paper will be used.

“Coated for glossy-coated papers, uncoated for plain uncoated paper, matte for paper with a matte finish. Different paper finishes will absorb the inks differently, so the inks are formulated slightly differently to compen-sate for that absorbtion.”

This is good to know about but in effect everything will be evident in the Pantone Swatches.

It is your job to determine what type of sur-face should be used for the print job. If there is aproblem with the colour choice then re-asses the colour using PMS and inform the printer.

A Pantone Swatch book shows the colour measurements for different surfaces. There are a whole range of any colour you can think of, and then a range of tones, tints, coats for that specific colour. Each colour is referenced with a code. This code is used by printers all over the world and is the most common use to com-municate the exact colour needed to avoid any confusion whatsoever.

As shown in the image, the best way to get an accurate colour for what you want to print is to physically match the colour to what you see in the swatch book. Once matched, the reference code can be typed in to your design software ie Illustrator, Photoshop, Indesign etc. All the soft-ware you will come to use most probably use this system, especially the Adobe programs.

There are ways around a wrong colour matching. Before printing the design officially, your artwork will go through a proofing stage. This is as close to the finished print as you will get on another stock.

From the point of discussions and final approval of the proofs/examples for your client, you can then press-pass the project. A press-pass is when the artwork is going through the printers press on the actual stock using the print process you have specified, you are able to check the first sheets through the press. You can approve the project, slightly adjust the colours or if the reproduction/stock is not correct or successful, the process can be stopped and the artwork adjusted at the final artwork/repro stage. A differ-ent process and paper stock can be specified to meet the requirements of clients brief and objectives.

Proofs are great for showing your client how the work will look. The most useful part about reaching this stage is that it is the last point at which you can make amend-ments and minor changes. If the client is happy with this then it is their problem if the very final production stage, resulting in the print is not what they wanted - as they have declared they were happy with it.

Also, proofs are important incase the printer finally prints it wrong to how it looked on the proof. It almost acts as a contract for you to show them how they declared it would look, therefore giving you the upper hand in any confronta-tions or opinions they may have.

The colour will more than enough show an off colour on the screen - a colour that differs to the one you see on your surface. This is caused by the fact you cannot de-

termine the colour on the screen is what will be printed. If the col-our reference is correct on what you are designing, it will print that exact colour.

Linen Testers

A linen tester checks the quality of the print. The strong magnifier enables you to see the printed colours on a deeper scale. Often regarded as a printers best friend, every graphic designer should have one.

“Linen Testers, as the name suggests, were first introduced to assist in the textile trade. More recently they are used extensively in the print trade and photography, to test the quality of the paper and the pixels respectively. A Linen Tester is also the most useful type of Magnifier for looking at watermarks, stamp perforations etc.”

A traditional printers tool for assessing print quality such as ink acceptance, dot structure and fit.

They are instruments that allow you to inspecta print. This is important to be sure that a print is to the cor-rect standard, measuring the line width and checking the registration of colour seperations. The magnifier gives you an insight into how printing functions. For example, when inspecting a colour photograph, the 4 colour seperation can be seen. This being the small dots of CMYK scattered across the page, so to the human eye an illusion emergeswhere the colours mix together to show an image.

Take the image above for example. The left hand side shows the photograph as we would see it normally.

However, looking deeper into it - using a linen tester - into a specific section, we can see the huge amount of colours (CMYK) that form something so miniture and decieving that human eye is unable to pick up, no matter how far or close you are.

Printing Methods

First off, it’s important to know what/who reprographics are. Put simply, they are the people inbetween artwork and technical print. They’re like the problem solvers before printing and useful contacts to be aquainted with, be their friend.

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ROTARY PRINTING

“In this process the image printing plates are wrapped around a cylinder. This is an auto-mated print process and the material to be printed can be sheet fed or on a roll.”

Offset lithography (Litho)Rotogravure (Gravure)Flexography (Flexo)

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The three main types of rotary printing.

Litho

Litho printing works on the basic principle that oil and water do not mix. The offset lithographic process works by first transferring an image photographically to thin metal, paper, or plastic printing plates. Unlike other forms of printing, in offset lithography the image on the printing plate is not re-cessed or raised.

Offset Litho explanaition:

“Etched aluminium plates wrapped around a cylinder transfer ink to an ‘offset’ rubber blanket roller and then to a print surface. Sheet fed or Web fed.”

Rollers apply oil-based ink and water to the plates. Since oil and water don’t mix, the oil based ink won’t adhere to the non-image areas. Only the inked image portion is then transferred to a rubber blanket (cylinder) that then transfers the image onto the paper as it passes between it and another cylinder beneath the paper.

The term offset refers to the fact that the image isn’t printed directly to the paper from the plates, but is offset or transferred to another surface that then makes contact with the paper.

Gravure

Copper plates (with mirror image) transfer ink directly to print surface, usually on rolls. Advantage, plates are more durable and so are good for long print runs. Gravure printing is a process in which the image to be printed (unlike in letterpress and flexographic print-ing) is etched into the printing plate, and the printing ink (unlike in offset printing) is transferred direct to the paper.

In gravure, a cylinder unit prints one colour on one side of the web, which is then dried in a hot oven before reaching the next unit In contrast, web-offset units print one colour on each side of the paper without drying between units, and all the ink is dried in one oven after the last printing unit.

Flexography

A positive, mirror image rubber polymer plate, on a cylinder, transfers ‘sticky’ ink di-rectly to print surface. Usually roll feed. Flexo is usually used on everyday packaging we use such as crisp packets and bottles.

Digital PrintingIdeally suited to short run or specials on a range of print media from paper to metal.

Pad PrintingA printing process that can transfer a 2-D image onto a 3-D object. Pad printing is used for objects from calculators to pens and pencils.

Screen PrintingA printmaking technique that uses a woven mesh to support an ink blocking stencil.

Screenprinting is one of the most common printing methods around. A printing company would normally have a series of screen print-ing beds surrounded in a circle so a series of prints can be printed continuously.

In some cases, there are actual screen print-ing machines that churn out fresh prints automatically. If not then the screens are controlled by a series of people printing vasts amounts of finishes for the designs.

Print Finishing

The print finishing takes place after the print stages. This may come in the form of laminating, image transfer, trimming and coating.

In commercial printing, print finishing is associated with folding, stapling, saddle stiching and perfect binding, varnishing, foil blocking, embossing or die cutting.

- All of which is an addition to the cost and look of a finished print job.

Special finishes Lamination and varnishing are employed extensively in brochure print-ing as both of these treatments will generally give a page a luster that adds a feeling off quality to a publication.

Lamination

Often with lamination you might not actu-ally see the laminate which is a thin plastic coating heat sealed onto the paper. You will however feel it as it creates a smooth and impervious finish. This will likely be a matt laminate. Gloss lamination is more readably seen and again adds to the tactile quality of a page. Often lamination is only used on a brochures cover as it can add considerably to the cost of a print job.

UV Varnishing

With both gloss and matt finishes available UV varnishing gives a similar effect to lami-nation although the process is more aking to printing a spot colour. With not quite the same feel as a laminate it has benefits in that it is generally cheaper to employ and can be printed on to discreet sections of a page such as a logo or image. Metallic Inks. These are again spot printed onto a page and can add a bit of oomph to a brochure when used judiciously. They have a reflective quality due to the metallic constituent in the ink. Available in a variety of pantone colours they are best employed fairly simple areas due to the viscosity of the ink.

Foil Blocking

A technique where metallic foil is applied to a page using heat and pressure to create a reflective area. The effect is usually more eye catching than a metallic ink as the foil has a greater reflective properties and sits on top of the paper rather than being partially absorbed as is the case with the ink. The down side of this is that it is more expensive than metallic ink requiring a special dye to be made and will often be carried out in a specialised workshop.

Embossing

The technique of raising up a portion of the page to create a shadow. This, like foil blocking, requires a special dye to be made and subsequently can add significantly to the overall cost of a job.

Die cutting

A metal tool which punches is hole or edge into a piece of artwork ito create a irregular shape in the substrate, usually card or paper. Like a pie cutter in application, A die cut-ter is often used used to create packaging from a regular sheet, but can also be used in brochure design to create an unusual cover or to knockout a hole for a image to show through. The cutter is a series of blades set in a block to create a single unbroken but irregular edge and can be combined with scoring to create folds in the paper. These have a significant make ready cost and are usually only used when a budget permits.

Costs

As with every situation in design, budget is a key factor in deciding how and why you are going to print. Taking into consideration the ways you could reduce the cost of your prints by using a limited number of prints and a cost efficient substrate. Make sure to shop around and enquire with printers as to what the going rates are.

Often your budget can be stretched well by taking into account these small details.

Looking back on the previous pages, each stage should be carefully considered, mainly to avoid incorrect printing and a smooth print run, in turn keeping your budget as tight as possible.

Obviously, finding different stocks to what other designers around you are using is important. Make note of how much stock is necessary for your print, reducing the risk of having needless scraps left over.

Double check with PMS as to how the colour will fair with the type of stock ie what the colour will look like on an uncoated type.

Without the risk of repeating what has already previously been stated, all of the fac-tors, from utilising linen testers to gaining an awareness of how designs differ on screen than print.

Costs, especially when working to a clients budget are what limit the designs end product, so taking full advantage of the logics and main principles of print will open up more avenues. Other ideas can be explored further than the design process, offering more options for yourself and the client to choose from.