RGB vs CMYK & Printing Colour Guide
Colour on a bright screen and colour printed with ink are produced in fundamentally different ways. Understanding that difference helps explain why some colours change in print, why brand colours need extra care and why the material you print onto matters.
RGB is light. CMYK is ink.
RGB and CMYK are not simply two different sets of colour numbers. They create colour differently, which is why the same design can appear different on a monitor and in print.
Why some colours change when printed
A colour gamut is the range of colours a particular colour system or device can reproduce. RGB and CMYK do not have identical gamuts. Some vivid colours displayed with light fall outside the range available to a standard CMYK print process.
Very bright blues, greens, oranges and other highly saturated colours can be particularly difficult to reproduce exactly with standard process inks.
When an out-of-gamut RGB colour is converted for print, it has to be mapped to a colour that the intended printing process can reproduce.
Your monitor is not a printed colour proof
A monitor produces light. Print reflects the light falling onto paper, vinyl or another material. The brightness and colour settings of the screen also affect what you see.
CMYK is a colour model, not one universal printed appearance
CMYK describes the use of cyan, magenta, yellow and black, but the exact colour those values produce depends on the printing conditions. This is why professional colour workflows use colour profiles.
If a colour really matters, tell your printer
A company logo may exist as a HEX value for a website, RGB values for digital use, CMYK values for process printing and perhaps a specified spot colour. These are useful definitions, but they do not mean every process and material will produce an identical physical result.
CMYK and spot colour are not the same thing
The same colour can look different on different stocks
Printed colour does not exist independently of the surface beneath it. Whiteness, texture, coating and absorbency can all influence the appearance of the finished print.
Lamination can change how colour is perceived
A laminate sits over the printed surface, so its finish affects the way light interacts with the print. Gloss, matt and other films can therefore alter the perceived depth, contrast and character of a colour.
This does not necessarily mean the underlying printed colour values have changed. The finished product simply reflects and diffuses light differently.
Small black text and large black areas are different jobs
Black deserves particular attention because a simple black-only element and a large deep-black graphic area may be prepared differently.
Common print colour mistakes
Check the exported print file, not just the design screen
Professional design applications provide colour-management controls, while simpler design platforms may handle conversion during export. Whichever software you use, the final PDF supplied for production is what matters.
Where available, choose the print-quality PDF option and appropriate print colour settings. If colour is critical and you are unsure how your software is handling it, send us the file before placing a colour-sensitive order.
Tell us before the job goes into production
Most everyday commercial print does not require exact colour matching. But if a corporate colour, product colour or previously printed item needs particularly close attention, let us know.
Send the artwork together with any known CMYK or spot-colour references and, where relevant, an existing physical sample. We can then advise on a sensible production approach and whether a printed proof or colour test would be appropriate.