If you are a designer, you should be familiar with the two colour models RGB and CMYK. While CMYK and RGB are two of the most prominent colour models used, there are many differences between the two.

RGB stands for red, green, and blue colours; in design, these colours are recognized as the primary colours.
RGB model is known as an additive model, where colours are added together to make up what we see on the screen. RGB is the colour scheme that is associated with electronic displays, such as monitors, digital cameras, and scanners, etc. A digital monitor is made up of tiny units called pixels. These pixels are comprised of three light units: one for red, one for green, and one for blue. The RGB values are applied to these pixels, thereby setting the luminosity for each of the light units in each pixel.

Light is projected through RGB by blending the colours on the eye’s retina to create the desired colours. When all three of the colours are combined and displayed, the result is a pure white. When all three colours are combined to the lowest value the result is black. Softwares such as photo editing programs use the RGB colour mode because it offers the widest range of colours.

CMYK, on the other hand, stands for the colours cyan, magenta, yellow, and black. CMYK is a subtractive model and with subtractive models, the colours from the spectrum are subtracted from natural white light into pigments or dyes. These pigments are then printed onto paper in tiny little cyan, magenta, yellow, and black dots. When the three colours (cyan, magenta, and yellow) are added together, the result is not pure black, but rather a very dark brown. The K colour, or black, is added.

CMYK is the primary colour model used by colour printers. Any printed media, such as flyers, posters and signs, are printed in CMYK, which means that images supplied must be in CMYK to stay as true to the colour as possible.

In conclusion, if you’re going to print something, such as a business card, stationery, or a newsletter, use CMYK. If it is something that will only be seen on the screen, use RGB.

If you are working in Photoshop or Illustrator, make sure you set the appropriate colour mode for the media you expect to present your work in. If your work is going to be printed use CMYK colour mode because the same design displayed on a computer monitor may not match to that which is printed in a publication.