RGB and CMYK whats the difference and when to use them

There are lots of different colour formats but RGB and CMYK are the two most important and typical (most used) colour formats used in design. It doesn’t matter if you work on the web, in print or edit videos you would have come across these colour formats and in this post I will explain what they are and also when it’s best to use to them.


RGB stands for Red, Green and Blue and is best suited for and typically used by electronic displays, monitors, computer screens etc. Screens are made up of red, green and blue pixels and process of addition can create can create millions of different colours, this is mainly done by varying concentrations of these colours with light. One of the problems with working in RGB is that because most screens are different with different settings, colours will look slightly (only slightly) different on each screen. There is an RGB web safe colour mode, which will look the same pretty much everywhere but will limit the amount of colours you can use.


CMYK stands for Cyan, Magenta, Yellow and blacK and is best suited for and typically used for printing; magazines, leaflets, brochures, books etc. The reason that there’s a K at the end instead of a B for black is because apparently most people at the time thought it maybe confusing, as people already think B is for Blue.

CMYK are the ink colours being applied to the paper, the mixture of the four colours produce the wide array of colours that you see on screen. The interesting thing I learnt about using the CMYK colour mode is that the black you get when everything is at it’s highest is a rather weak black and almost dark grey. Then I found out about rich black, which you achieve by having the C = 50, M = 50, Y = 50 and K = 100, there are other ways to get a rich black but it will come down to your printers settings.

I don’t know if you ever tried to print in RGB, I have and whenever I do I always end up looking at the printed version and the on screen one and they never quite match. Making and printing your (printed) work in CMYK will most likely fix this problem, but more than likely you will have to mess with some of the printer settings or even screen settings to get it just right.

RGB works best for any work that will end up on a screen and CMYK will be best for any work that will end up being printed out.

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