RGB Explained

Where CMYK is a subtractive system, RGB uses an additive property to create colours by combining the primary colours in varying degrees to create different colours. Much like painting for example, colour is added step by step to combine and create new colours, by adding more and more the colour changes depending on the colours added.

Levels of Red, Green, and Blue that can be added range from 0 to 100% of their colour. Each level is represented by the range of decimal numbers from 0 to 255, so 256 levels for each colour. So, doing my least favourite thing (maths) the total number of available colours is 256 x 256 x 256, or 16, 777, 216 possible colours.

Interestingly (to me at least), when all three colours are combined to their full extent, the result is white, as opposed to the black you achieve with CMYK, or when combining paints.

So, when combining all three colours to their lowest extent, the result is black. They’re essentially the opposite of one another – CMYK starts white and turns black, RGB starts black and turns white.

Still confused? Let’s go into a little more detail…RGB colours are known as an additive, meaning they are created with light. Additive colours start off black and, as colour is added, they turn lighter and lighter until they’re white. The screen you’re currently reading from shows colours made of light.

Generally speaking, where CMYK is the printing standard, RBG colour models are most often used in electronic devices as the screens tend to be darker. Combining red, green and blue light produces lighter colours, working in contrast to the dark screens. A digital monitor is composed of tiny pixels, which are comprised of three light units, red, green and blue. When applying the RGB values to these pixels, you are setting the luminosity for each of the light units in the pixel, determining the colour of it.