Designing something that looks good on screen is only part of the job. When artwork is going to be printed, there are technical considerations that can affect colour, size, image quality, cutting and the final appearance of the finished piece.
For anyone learning graphic design, understanding these basics is just as important as knowing how to create an attractive layout. A file can look perfect on screen and still produce unexpected results when it reaches the printing press.
This guide explains some of the key things to consider when preparing artwork for print, from CMYK process colour and bleed to cutter shapes, image resolution and press-ready PDFs.
One of the first things to understand is the difference between RGB and CMYK colour.
RGB stands for Red, Green and Blue. It is an additive colour system used by screens, phones, cameras and other devices that produce light. Colours are created by combining different amounts of red, green and blue light.
Printed material works differently.
CMYK stands for Cyan, Magenta, Yellow and Key (Black). These are the four process colours used in conventional four-colour printing.
Instead of producing colour with light, printing builds images by applying combinations of coloured inks to the paper.
This means a bright colour that looks excellent on a monitor may not reproduce exactly the same way when printed.
In lithographic printing, CMYK process colour uses separate printing plates for cyan, magenta, yellow and black.
The four colours are printed in carefully controlled amounts and, when viewed together, create the appearance of a wide range of colours.
The individual dots of ink are generally too small to be seen clearly from a normal viewing distance. Our eyes perceive them as continuous areas of colour.
This is one reason why artwork intended for lithographic printing needs to be prepared with the printing process in mind.
A photograph, for example, may contain thousands of colours, but when it is reproduced using CMYK process printing, the image is separated into the four process colours.
Not every printed colour has to be created using CMYK.
A spot colour is a specific ink colour that is printed separately rather than being produced by combining the four process colours.
Pantone colours are a familiar example of a spot-colour system.
Spot colours can be useful when an exact colour match is important or when a design requires a colour that is difficult to reproduce accurately using standard CMYK process printing.
They can also be used for specialist printing requirements, depending on the printer, paper and production method.
When preparing artwork, it is therefore important to know whether a colour has been specified as a process colour or a spot colour. An unnecessary spot colour can create an additional printing plate and potentially increase production costs.
One of the most common technical requirements when preparing artwork for print is bleed.
Bleed is the area of artwork that extends beyond the final trimmed size of the printed piece.
For example, if a document is being produced at 210 × 297 mm (A4) and the printer requires 3 mm bleed on each edge, the artwork extends beyond the finished page size.
The final sheet is printed larger than the finished document and then trimmed down.
Because cutting is a physical process.
Even with modern guillotines and accurate production equipment, there can be very small variations in the position of the cut. If a photograph, background colour or graphic finishes exactly at the edge of the document, even a tiny movement could leave a narrow white line along one side.
Bleed gives the printer some extra image area to trim away.
The important point is that 3 mm bleed is not automatically required for every type of print. The specification depends on the printer, production method and job.
Always check the printer's artwork requirements before preparing the final file.
Crop marks, also called trim marks, indicate where the finished printed piece should be cut.
They show the printer or finishing department the intended final dimensions of the artwork.
Crop marks and bleed work together:
A common mistake is to add crop marks manually without understanding how the document's bleed and export settings work. In most professional design applications, the correct approach is to define the document size and bleed correctly and allow the application to generate the appropriate marks when exporting the print-ready PDF, if the printer requires them.
Bleed protects elements that run off the edge. The opposite problem is placing important information too close to the edge.
Text, logos and other essential information should normally be kept safely inside the trim area.
The required distance depends on the printer and finishing method, so again, the printer's specification should take precedence.
Think of the page as having three areas:
Important information stays safely inside. Backgrounds and images that need to run to the edge extend into the bleed.
Not everything is printed as a simple rectangle.
A folder, presentation wallet, shaped card, packaging sleeve or promotional piece may need to be cut into a specific shape after printing.
This is where a cutter guide or die-cutting shape is required.
A cutter shape is essentially a technical outline showing the finishing equipment where the material needs to be cut.
For example, if a piece of packaging has a curved edge, a circular window or a custom shape, the printer needs accurate information showing exactly where those cuts need to take place.
The artwork and cutter guide therefore serve different purposes.
The artwork contains the visual design.
The cutter guide contains the production information needed to create the physical shape.
A cutter guide is normally set up as a separate technical element, often using a dedicated spot colour and clearly named according to the printer's specification. The exact setup can vary, so the printer's requirements should always be followed.
Because the edge of a design is not necessarily the cutting instruction.
A photograph or graphic might have an irregular visual edge, while the physical product requires a precise die-cut shape.
The cutter guide tells the printer exactly what needs to happen during the finishing process.
This distinction is particularly important when designing packaging, folders, shaped promotional pieces and other bespoke printed products.
Images used in print need to contain enough information to reproduce clearly at their intended size.
A low-resolution image may look acceptable when viewed small on screen but become soft or pixelated when enlarged for print.
Resolution is usually discussed in pixels per inch (PPI) for digital images.
The important point is that resolution needs to be considered in relation to the final physical size of the image.
An image that is suitable at a small size may no longer contain enough information if it is enlarged significantly.
The terms PPI and DPI are often used interchangeably, but technically they refer to different things.
PPI (pixels per inch) describes the resolution of a digital image.
DPI (dots per inch) is associated with the dots produced by a printer or output device.
For preparing photographic images for print, PPI is generally the more relevant term.
Understanding the difference between vector and raster artwork is also useful.
Raster images are made from pixels. Photographs are usually raster images and are therefore affected by resolution.
Vector artwork is created using mathematical paths and shapes rather than a fixed grid of pixels.
Logos, icons, illustrations and other graphic elements are often best created as vector artwork because they can be scaled without becoming pixelated.
This makes vector graphics particularly useful when the same artwork needs to be reproduced at different sizes.
Black can be handled in different ways in CMYK artwork.
For some text and fine detail, 100% black (K) is appropriate.
Large areas of black may sometimes be produced using a combination of CMYK inks, known as a rich black, to create a deeper appearance.
However, the exact combination should not simply be chosen at random. Too much total ink coverage can cause production and drying problems depending on the printing process and paper.
This is another example of why artwork should be prepared according to the printer's specification rather than relying on assumptions.
Fonts also need consideration before artwork is supplied for print.
If a font used in a document is unavailable when the file is opened elsewhere, text can reflow or substitute with another typeface.
Professional workflows can deal with this by embedding fonts within the PDF where appropriate or converting text to outlines when required.
However, outlining text has disadvantages too. Once text has been converted to outlines, it is no longer editable as text.
It is therefore important to follow the printer's preferred workflow rather than automatically outlining everything.
Modern design software allows designers to use transparency, shadows, blending modes and other effects that may look straightforward on screen but require careful handling when artwork is output for print.
Overprinting is another technical consideration.
An element set to overprint does not knock out the objects underneath it in the normal way. This can be useful in some circumstances, but an incorrect overprint setting can produce unexpected results.
Small black text, for example, is often handled differently from larger coloured objects.
This is why checking the final PDF rather than relying only on the original design file is important.
Once the artwork is complete, the final step is normally to create a PDF suitable for the intended printing process.
The exact PDF settings depend on the printer and production method.
A print-ready PDF may need to contain:
PDF/X standards are commonly used in professional print workflows because they provide defined requirements for exchanging print-ready PDF files.
However, there is no single PDF export setting that is correct for every printer and every job.
Always ask the printer what specification they require.
Before sending artwork to print, it is worth carrying out a final preflight check.
Ask yourself:
A few minutes spent checking a file can prevent much bigger problems later.
One of the most important lessons when learning graphic design is that a screen is not a sheet of paper.
A monitor produces light. Paper reflects light.
The colour you see on a backlit screen is therefore not a guarantee of exactly what will come off a printing press.
Paper stock, ink, printing process, coating and finishing can all influence the final appearance.
This is why professional print design requires an understanding of both visual communication and production.
The designer needs to think beyond the artwork on the screen and consider what happens when that artwork becomes a physical object.
Preparing artwork for print is not simply a case of pressing Export PDF.
Understanding colour, bleed, trimming, resolution, fonts, cutter guides and PDF preparation gives designers much greater control over the finished result.
For students and designers beginning to work with professional printers, learning these principles early can prevent common mistakes and make the transition from digital artwork to physical print much easier.
The best print artwork is designed with the finished product in mind from the beginning — not treated as an afterthought once the design is complete.
If you're looking for professional help with a print project, you can find out more about our [Print Design Services in Glasgow].