RGB vs CMYK

RGB or CMYK?

Often people have come to us quering the difference between these colour modes and what they should use. The color systems used by scientists and artists are entirely different.

An artist will mix blue and yellow paint to get a shade of green; a scientist will mix green and red light to create yellow. The printed page in a magazine is yet another system.

As a designer and printer, it is essential to know when to use RGB vs CMYK. But very few designers and clients know why.

In the print industry, cyan, magenta, yellow and black are used as the primary colours. The CMYK is used in colour printing, and is also used to describe the printing process itself.

CMYK refers to the four inks used in some colour printing: cyan, magenta, yellow, and key (black). CMYK is a colour model in which all colors are described as a mixture of these four process colors. This colour model is subtractive meaning that the more ink added, the closer you get to black. Use CMYK if you are sending your photo to be printed, such as preparing a postcard to be professionally printed for a gallery invite. 

In contrast, display devices generally use a different colour model called RGB, which stands for Red-Green-Blue. Use RGB if you are taking photos specifically to be viewed onscreen, such as the internet, or for a CD or emails.

RGB is know as 'additive', meaning that the more RGB light beams emitted, the closer you get to white. If no light is emitted (RGB 0 0 0) you will se black. If maximum light is emitted (RGB 255, 255, 255) you will se white. RGB values range from 0 to 255. One of the most difficult aspects of desktop publishing in color is color matching -- properly converting the RGB colors into CMYK colors so that what gets printed looks the same as what appears on the monitor.

But the standard still stays the same – use CMYK on all printing needs, as the color will appear differently if printed in RGB. Here at eColourPrint we convert all files into CMYK ready for printing. The same art displayed on a computer monitor may not match to that printed in a publication and this is all due to RGB and CMYK.