Colour Theory

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The 3 Primary colours in digital imagery are Red, Green and Blue. RGB. Not the primary colours as we know them to be, Red, Yellow and Blue. This is because Red, Green and Blue are the colours found in the human eyes colour photoreceptors.

If you shine a Red torch slightly overlapping a Green torch, then slightly overlapping a Blue torch, shining 3 equal parts of the primary colours will create white colour. The photography below shows this.

Adding equal parts of the primary colours, white is seen, this is the basis of Additive colour. When working on a computer screen the colours are created with light. Additive colour mixing begins with black and ends with white. Taking away these colours the black is seen. By combining different quantities of these primary colours, brighter colours are made.

The chart above shows the primary colours and secondary colours that can be created with 2 equal parts of primary colours.

Blue + Green = Cyan

Green + Red = Yellow

Red + Blue = Magenta

The basis of subtractive colour mixing means that you begin with white and end with black. If you look at painting or printing, you start with white paper and add colour. For printers you will generally have 2 cartridges, one tri colour-CMY and one black. CMYK. When mixing Cyan, Magenta and Yellow you achieve a very dark colour, however it isn’t a true black. That is why you need an additional black cartridge. The K from CMYK stands for black (taken from the last letter in black so not to get confused with blue, B in RGB).

Colours that are next to each other on a colour wheel are known as colour harmonies. These colours will sit nicely together and compliment each other. Colours that are opposite each other on the colour wheel create a colour contrast. Contrasting colours are often used in advertising and logos. They compliment each other and create a visual contrast that captures your eye and therefore you notice them.

Yellow is used a lot in advertising due to it being one of the strongest colours. When we see yellow our eyes have to re-adjust. It will always stand out and therefore influence the viewer.

The First Colour Photographs

James Clerk Maxwell 1831-79

James Clerk Maxwell was a Scottish scientist that produced the first colour photograph in 1861.

Maxwell used the three colour method. Taking a photography with a Red filter, then a Green filter and then a Blue filter. When all three images were super impose together and a white light shone through, colours were seen. The photograph below was that image.

Sergey Prokudin-Gorsky 1863-1944

Sergey Prokudin-Gorsky really expanded on Maxwell’s colour vision and produced many early colour photographs.

This photograph below was taken in 1911 by Gorsky as part of his documentary work on the Russian Empire.

Three separate black-and-white photographs were taken through Red, Green then Blue filters. Then on a projection screen, these three photographs were combined to create a full colour Image.