16 page printing guide: content

I spent the last couple of days going through my research and reflecting on what I had learned in the past few weeks, and I am quite pleased with what I have written here. The final word count sits at around 3,000 words, and me being academically challenged has found it difficult to write about.

I didn't want to write out step by step guides on all the things to do with colour as my words show my understanding of the processes involved in designing for print. I don't expect people to read the full amount of content but I am simply posting this as part of my research findings, and put what I've learned into context.

I did pick and choose what I featured in my articles based on what I found useful to me, and I had to leave it things like trapping, and colour half tones to accommodate for space and not have too many topics on one page.

Now I have my content I can start to decide on the scale of my publication, putting together layout ideas (columns, margins, gutters, etc) , as well as calculate how my type will fit and the page, etc.

so here is my full content...

1
Print.
An introduction

2–3
Index
• An introduction to basic colour spaces
• Pantone & Spot colours
• Creative colour processes
• Help! I’m preparing colour for print
• An Overview: Printing Processes
• Feature: Lithography in practice
• What Substrate?
• Print Finishes

4-5
CMYKVSRGB
The two most common colour spaces found on a computer are RGB & CMYK.
But why do we need them and what is the difference?

The RGB colour gamut can reproduce 70% of the colours that can be seen with the human eye. The RGB palette is made up of red, green and blue light and is known as an additive colour space. Everything from monitors to digital cameras use an RGB colour space, as the gamut is wider than a CMYK colour space. This means the images we see on screen are made up of a wider spectrum of colours and produce a more saturated image due to the intensity of the colours. RGB is primarily used for web based graphics.

CMYK is a subtractive colour space used by mixing Cyan, Magenta, Yellow and Key (Black) colours. This colour system is used solely for print and its gamut is much smaller than RGB. The restrictive gamut means a smaller number of colours can be printed. There are ways in which we can print specific colours outside the CMYK gamut known as Pantone® and Spot colours (page 6-7). By mixing all 4 process colours together we can make a deep black, known as registration black, which is used predominantly for registration marks.

It is important to know which colour space we are working in if working for print or web. For example if we were to produced a document for print using an RGB colour space, then the colours within the document that were outside the CMYK gamut would be converted to the nearest colour within the CMYK colour space.

6-7
Pantone & Spot Colours
Pantone and Spot colours are commonly used by graphic designers to ensure that a certain colour will print accurately if it falls outside the CMYK four colour process colour gamut. A spot colour is any colour generated by an ink, which is either pure or mixed from other inks. Special colours such as these require a specific colour mix and are often used if a vibrant colour is required. Pantone colour swatch books feature all the colours in the pantone range. These colours can sometimes be matched accurately to a process colour. However, if a colour is critical, for example in a corporate identity, then a spot colour ink chosen from the pantone sample book can be chosen. Each pantone colour has a reference number and is recognised on software such as the Adobe Creative Suite.

Pantone colours are supplied in solid, pastel and metallic colours amongst others. There are also different types of colour depending on the substrate (16-17). These include coated for a glossy stock, uncoated for an uncoated stock, etc. This is because different substrates can make the same colour appear differently.

8-9
Creative colour processes
Tints
Leading on from our discussion surrounding pantone and spot colours, we can use these colours creatively to make a 1 colour print seem more complex through the use of colour tints. We can make tints from any pantone colour and also Cyan, Magenta, Yellow and Black when used in isolation. For example the diagram shows a 100% Cyan ink which has a 10% reduction which makes that 90% Cyan. The next box down is then 80% cyan, and so on until it reaches 10%. I would not make any more percentage reductions after this point as the colour becomes too opaque. We can repeat this for any single colour ink.

Mono & Duotones
We can use other creative colour processes such as Mono tones, and Duo tones to change the look and feel of an image, and this can be handy to use if we have a set colour palette to work with. For instance, if we are to produce a poster with just two colours like (insert colours here) then we could also produced imagery that only uses these two inks. This means that the print job would be cheaper than using a full 4-colour process. Below are examples of Mono tone and duo tones. Effectively two different colour Mono tones overprinted (pg11) would create a duo tone print. We can also create Tri tones and even Quad tone prints. We can also use selective duotones by manually selecting parts of an image using spot channels to colourise that part of the image.

10-11
Overprinting
Overprinting is a basic function that can add graphic effect. The best overprinting examples are usually done with typography as they use solid colours. As the graphics are layered upon one another the colour will change depending on the colours that are overlaid. Overprinting in graphic design for print is common on posters. By default objects and type that overlay one another usually ‘knockout’, i.e. the colour printed on the layer above will always printed instead of the colour below it. Design programs such as Illustrator and InDesign have overprint functions, and software such as Photoshop can achieve a similar effect by using blending modes. Overprinting onto black would not make any noticeable difference to the black colour. Although, when the other 3 process colours are overprinted onto black, the black becomes stronger colour. Overprinting using images, vector graphics and gradients can also be achieved with good results.

Help! I’m preparing colour for print
There is a list of pointers that can help you prepare a document ready for print when using colour. These prepress checks are a must for all designers because if it is wrong you could incur the costs.

1. Delete all unused colours – The colours in your swatch panel should correspond to the document you are working on. If you are working on a two colour print job and using 2 spot colours for instance, make sure that the rest of the colours like Cyan, Magenta, Yellow and Key are deleted from the swatch panel.
2. Ensure all you want to print is in black and not registration. For instance if you are preparing artwork that is a solely black, you will need to make sure the artwork is in black only. Sending artwork that is fill with registration will utilize the full four colour process.
3. Ensure all you to print in registration, is in registration. This is the opposite of the last point but registration prints as a much richer black than using ordinary black ink.
4. Ensure all spot colours are accounted for. If you do use a special colour, this is fine but don’t send artwork with unused spot colours. Spot colours can be assigned to be print as spot varnishes and other print finishes. Make sure the printer knows of this.
5. Ensure all images are converted from RGB to CMYK as colours can appear differently to how they looked on screen. The colours that were accurate on screen may now be out of gamut and would be substituted for the next nearest colour.
6. Ensure any colour swatches that you imported from one program to another hold the same value. Make sure that any pantone uncoated colours are to be printed on uncoated stock.

12-13
An Overview: Print Processes
The four main industry standard print processes are known as Rotary Printing, which includes Offset Lithography (pg 14-15), Flexography and Rotogravure, Digital Printing, which is prints digitally which prints in a similar way to your printer at home, Screen Printing, which uses screens to print from by layering inks and is often used for t-shirts and generally anything that is difficult to print digitally, and Pad Printing, which takes ink from a plate and transfers it to a pad, which then can be transferred to a variety of substrates either 2 or 3D.

All the four processes are set up to print differently and better suited to particular jobs. For example if you were to print limited edition run of posters on a thick stock, you may decide to print using screen-printing. Screen-printing is suited to limited print runs but can produce a better quality than digital printing.

Screen Printing
Screen printing is a print process which consists of ink being forced through a screen, traditionally made from silk. Today, the screens are usually made from a synthetic fabric, which is more cost effective and longer lasting. The screens are coated a photo emulsion, which hardens when subjected to UV light.

Setting up printing screens can be costly so it is not cost effective to produce a screen for a one-off print job. A new screen has to be produced for each ink colour you decide to use and the design you are printing will have to be transferred to the screen by exposing it to UV light for a number of seconds. For example, if you were to print a full colour image, you would need to separate the colours into cyan, magenta, yellow, and key channels digitally using graphic design software such as Adobe Photoshop and then printing the four colour separations separately onto acetate sheets ready for exposure. These are printed in grayscale because they only act as a stencil for your final design.

The screen is exposed and where light cannot penetrate through the stencil the emulsion does not harden like the rest of the screen. After this process, the screen is washed and the emulsion that has not hardened falls away to reveal your artwork on the screens ready for printing.

Digital Printing
Digital printing is more familiar to us as we take advantage of it everyone day if we ever want to print anything from a computer. Digital printing works in the same as our printers, just on a much bigger scale. Digital printing can be a cost effective way to print a one off, and can also be used to print large scale banners. Most large format digital printers can print up to A0, which is twice the size of A1. Canvas and PVC banners are usually printed digitally due to them being produced in 1’s and the fact digital printing allows us to print them in any length.


Pad Printing
Pad 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 printing plate via a silicone rubber pad onto a substrate (surface to be printed). Pad printing is used for printing on otherwise impossible products in many industries including electronics, appliances, sports equipment and toys. The plates can either be etched using a laser or hardened using UV light. The latter technique lasts much longer than the laser etched plates, so would be more costs effective for large print runs.

Rotary Printing
Rotary printing is common in the world of newspaper and magazine printing and has three main types all of which suit one print job better than another. The principle of rotary printing is nothing new but more viscous inks and improvements in technology means a better quality of print, better accuracy and faster production means it will be used for many years to come. Two large cylinders known as the impression roll and the gravure cylinder turn in unison to allow the paper to glide through. The gravure cylinder will be partially submerged in a large inkwell. This drum will apply the image to the substrate via the plate that is wrapped around it with the artwork etched onto the surface. The materials used to make the plate depend on the printing process being used.

Rotogravure
Rotogravure is a common commercial relief printing process in which an image is engraved into a copper printing plate (that’s why the plates are so durable) and is pressed directly against the substrate. Small cells are engraved into the plate that holds the ink ready to be transferred to the stock. It is a high speed print process that delivers a high volume of production and has the widest print presses. It is used for substantial print runs, such as newspapers and magazines.

Flexography
Flexography is printed using the surface differences in the plate. The process creates a rubber relief of the image, which is inked and pressed against the substrate. It was developed for printing packaging and traditionally gave poor results but now it competes with the likes of rotogravure and lithography, particularly as it can print a wide range of substrates due to the flexibility of the plate. It is often used for medium to large sized print runs. This print process is used for printing onto 3D objects such as soft drink cans and food packaging.

Rotogravure and flexography print processes uses lower viscosity inks than lithography so the drying time is much faster.

14-15
Lithography in practice
Invented in 1796, Lithography has grown with the times from using fat and oil to now where the image is made of polymer that is applied to anodized aluminium plates.

Lithography is the most versatile print process and the most commonly used for short to medium print runs. It produces good photographic reproduction and fine linework. It works by taking an inked image from a printing plate and then transferring or offsetting it on to a rubber blanket roller. This is then pressed against the stock or substrate. Lithography plates are smooth and works on the basis that oil repels water. When the plate passes under the ink roller, non-image areas that have a water film repel the inks which stick to image areas.

Lithography is considered to be the most commonly used process because plates are easy to prepare and the cost of printing is relatively low. Lithography printers can either be sheet fed or have a continuous web feed. A Sheet-fed method would be used for a small print jobs including flyers and brochures, where as web-fed presses would be used for newspapers, magazines and reports because of the high volume.

The problems incurred by using lithography are that the plate can start to suffer due to usage on high volume print jobs particularly when using a web-fed system. This can have cost implications as more plates would have to be produced. However, if used effectively the cost can be significantly lower than using a gravure technique.

16-17
What Substrate?
Stock is a major factor and can make or break a piece of printed design. In short, you as the designer, should always try to make your artwork look as good as it possibly can whilst keep the cost under budget as much as possible.

There are many varieties of paper stock but two main ones are coated and uncoated stocks. One of the first decisions a designer has to make is whether to print onto a coated or uncoated paper depending on the budget. Paper characteristics that affect printability include its smoothness, absorbency, opacity, and ink holdout. The substrate we use can affect how our work is viewed. For example, if we were to design a flyer or brochure discussing organic produced, we would look to use a natural stock that had not been chemically treated like the usual printing papers we can buy. The substrate would probably remain uncoated as well. Uncoated stocks generally absorb the ink much better than coated stocks.

There are other finishes to chose from such as wove, which has a uniform surface made by a woven wire roller that presses the paper. Woven substrates are coated and are suited to stationery and book publishing. Laid paper is a premium quality paper with a textured pattern of parallel lines similar to hand-made paper and is suited to business stationery. Bond stock is an economic uncoated wove paper often used for copying and laser printers. A higher quality bond stock can be used for letterheads.

The weight of the paper stock you select also comes into question depending on the printed materials end function. The system for measuring how thick the stock is GSM (Grams per square metre). The higher the GSM value the weightier the stock will be. Choosing the correct GSM to fit the purpose and the budget can be tricky at first. If you were to produce a leaflet on a fairly small budget, for example, you would have to select a paper that was opaque enough to be duplex printed without holograms appearing on either side, however, it also has to be flexible enough to fold. Selecting coated or uncoated papers may be decided upon whether your artwork is full of colour. Folding a coated paper with a solid colour may crack and be unsightly where as using an uncoated paper may not work because it could be distributed in a place where it could become wet or dirty.

There are many, many more types of substrate we can print depending on the print process we decide to use from recycled paper stock to wood free paper stock.

18-19
Print Finishes
Print finishes can add a special touch to your printed artwork whether it is through the use of foil blocking, spot varnishes, die cutting, binding, and embossing among others. Although the application of print finishes signals the end of the production process, these techniques should not be considered an afterthought. They are an integral part of the design at a planning stage.


Foil blocking
Foil blocking or foil stamping as it is sometimes known, is a process by which a coloured foil is heat pressed onto a substrate via a heated die. Foil blocking can add to a finish’s desirability particularly if it contrasts well with the colour of the document. For example a metallic silver foil blocking usually works rather well on a solid black finish. The process is versatile and can be used for typographic areas and can be used in conjunction with embossing to add a professional and high quality feel to a heavier card stock like a book cover.

Spot Varnish
Spot varnishes can be applied in the same way that ink is applied to a stock. They come in various forms depending on the substrate they are to be printed on. The varieties include gloss, matt, pearlescent, textured, neutral and UV varnish among others. They are used to give a glossy finish to a certain area and often work well when applied to typography to make it stand out against an uncoated stock. The can also be applied to images because they make the colours appear more vivid, and in turn appear much more saturated and sharper.

Spot varnishes, in some cases, can also be used in place of an ink. For example if you were to have a completely solid black finish on an uncoated stock, you could apply a spot varnish instead of a colour to typography and the shine of the varnish would make the typography stand out when light was reflected off the front of it.

20
Back cover
Continues from front