Firstly, you need to understand the difference between RGB and CMYK. RGB (Red-Green-Blue) is the colour system used on computer monitors, TV screens and digital cameras. It has the ability to show exactly 16,777,216 colours and as it is lit from behind, each colour is bright and vibrant. CMYK is used on printed material (a magazine or leaflet for example). Cyan (blue), Magenta (pink), Yellow and Black (the K stands for K colour) are used in varying quantities and can accurately portray anything from flesh tones to landscapes. CMYK has a far more limited colour gamut (range) than RGB.
How does this affect me?
You may find that the colours look different on a PDF proof that you have printed out to what you see on screen. There are many reasons for this, but the fundamental point is that the colours on screen will be much brighter and more vivid due to the difference between RGB and CMYK. In addition, the types of ink used in desktop printers may vary between manufacturers and are vastly different from the inks used on a printing press. Different papers and finishes will also change the way colours will look.
What can I do in future?
We always recommend a proof from the printer for any job where colour is an important factor. There are various types of proofs for colour matching and we will be writing a blog post on these in the near future. If you would like to chat through the differences and how they might affect you, we’re always on hand, even if you don’t have a definite project in mind.