Colour is where screen design and print part ways. A design can look perfect on a good monitor and still print duller, darker or slightly off-brand, and the cause is almost always physics rather than the printer. A few principles of colour for print save reprints, client complaints and a lot of back-and-forth.
This guide covers the colour theory that matters once a file goes to a trade printer: how screens and ink make colour differently, which colours shift and why, how to hold a brand colour, how the material changes what you see, and how to choose colours that read well on a sign.
Mediapoint is a trade-only wide-format printer in Derrimut, Melbourne. Since 2006 we've printed signs, banners, labels and stickers for designers, print resellers and agencies Australia-wide — white-labelled and blind-shipped, so your clients only ever see your brand.
Additive vs subtractive: why RGB and CMYK differ
Screens make colour by adding light. Red, green and blue light combine towards white, which is why RGB can show very bright, saturated colours. Print works the other way: cyan, magenta, yellow and black inks sit on a white surface and absorb (subtract) light, so the more ink, the darker the result.
The range of colours a system can produce is its gamut, and the CMYK gamut is smaller than RGB. Electric blues, vivid greens and bright oranges sit outside it, so when an RGB file is converted they move to the nearest printable colour and look flatter. That is why we recommend setting artwork up in CMYK from the start: you see the printable colour while you design, not after the job is printed.
Hold brand colours with Pantone Solid Coated
For brand colours that must match from job to job, specify Pantone Solid Coated (C) references in the file. At Mediapoint, our colour profiles detect Solid Coated Pantones and replace them with the closest match our digital process can print. CMYK values and other Pantone books print as supplied, so they don't get that replacement.
Use a Pantone Bridge guide when choosing. It shows the true Pantone ink beside its closest CMYK equivalent, and that CMYK swatch is the realistic target for digital print. Some Pantones, especially fluorescents, metallics and very saturated oranges and greens, sit outside what four-colour digital printing can reach. If a brand depends on one of these, tell the client early. Our colour matching guide covers the process in more detail.
The material changes the colour
The same file looks different on different materials, because the ink sits on the surface and the surface shows through.
- Gloss vs matt: gloss vinyls and laminates make colours look deeper and more saturated; matt surfaces look softer and cut glare.
- Mesh banners: mesh has open holes so wind can pass through, so a printed mesh banner reads lighter than the same artwork on solid PVC, especially up close. Bold colours and strong contrast carry best. See our mesh banner guide.
- Clear and silver labels: on clear or silver stock, whatever sits behind or under the ink affects the colour unless white ink is printed first. Our roll label artwork guide explains how to set up white ink.
Black is not one colour
Small text should be 100% black (K only) so it prints crisp, with no risk of four inks sitting slightly out of register. Large areas of solid black are different: K alone can look slightly grey, so designers often use a rich black that adds some cyan, magenta and yellow underneath. Check your printer's preferred rich black before using one, because too much total ink can cause drying and finishing problems.
Contrast and legibility on signs
Colour on a sign has a job: to be read from a distance, often in a couple of seconds.
- Contrast in lightness, not just hue. Dark text on a light background (or the reverse) reads from much further away than two colours of similar lightness, such as red on green or blue on purple. Convert the design to greyscale as a check: if the text fades into the background, the contrast is too low.
- Design for colour-blind viewers. Red and green are the most commonly confused pair. Don't rely on colour alone to carry the message.
- Use fewer colours on large formats. Bold, simple palettes carry further than subtle gradients, which flatten out at a distance.
- Think about the light. Outdoor signs face sun, shade and night lighting. Very dark colours lose detail in shade; very pale ones wash out in direct sun.
Closing the gap between screen and print
- Calibrate your monitor and turn the brightness down from maximum; most screens are set far brighter than a printed surface.
- Soft-proof in Illustrator or InDesign with View > Proof Colors to preview the CMYK result.
- For repeat jobs, keep the same colour values and the same material each time; changing either changes the result.
- For colour-critical work, test on the actual material before committing to a large run.
For the file setup itself, read print-ready files in Illustrator and bleed and crop marks explained. To see live trade pricing, open a trade account.
