The difference between RGB and CMYK

Understanding RGB & CMYK in Printing

RGB refers to the primary colours of light, Red, Green and Blue, that are used in monitors, television screens, digital cameras, and scanners. CMYK refers to the primary colours of pigment: Cyan, Magenta, Yellow, and Black. These are the inks used on the press in "4-color process printing", commonly referred to as "full colour printing" or "four colour printing".

The combination of RGB light creates white, while the combination of CMYK inks creates black. Therefore, it is physically impossible for the printing press to exactly reproduce colours as we see them on our monitors.


RGB to CMYK conversion

Many programs have the capability to convert the layout/images from the RGB colour space to the CMYK colour space. We request that you convert your colours from RGB to CMYK if your tools allow you to. By doing it yourself, you have maximum control over the results. You may notice a shift in colour when converting from RGB to CMYK. If you do not like the appearance in CMYK, we recommend that you adjust while working in CMYK (usually lightening).

Generally, you should specify CMYK colour builds that look a little lighter than you want, since the dots of ink "fatten up" on press, giving you more pigment on paper than you see on your monitor. Be especially careful to keep backgrounds light if there is black or dark coloured text over it, so that the text remains readable.

Should you not convert your files to CMYK we will convert as best possible when the file is prepped in our workflow system however we hold no responsibility for any colour accuracy whatsoever as our conversion may convert colours differently to what you require.


Will the colours match a sample I print out on my own printer, or a previously printed sample?

We calibrate our presses and equipment to a very rigorous industry standard for ink density and colour called ISO standard. Due to variation in conditions and equipment, we do not recommend using home or office printers to predict how images or colour will render when printed at our facility.

If you require precise colour match, please contact us to arrange for a hardcopy colour proof called a FOGRA. We will produce and send you a hard proof on equipment calibrated to our standard. When you approve and return the proof, we will strive to match the colour of the proof when printing your final piece. Please note that we can only provide this proof for coated stocks as it is not accurate for uncoated stocks like bond or cartridge papers.

There can be additional charges for precise colour match services. Also, if you request colour correction or other changes after you see your proof, there will be charges for colour correction time and a new proof.