A study in colour - Part 7 - The colour wheel in photography and white balance
The three primary colours (RGB) and secondary colours (CMY) make up the colour wheel. The colour wheel in photography involves all the colours you can make with the three primary colours red, green, and blue (RGB). There is an excellent image showing the relationship between the primary and the secondary colours (YMC) here . If you look at the image above, you can see the colour cast I added to the surrounding images. Opposite colours are diagonally located (green and magenta are opposites). Combining two of the primary colours produces a secondary colour. For example, if you combine red and blue, you get magenta. The same is true for red and green (yellow) and green and blue (cyan). If you subtract opposite colours, you get the opposing colour (if you subtract cyan, you get red). Adding opposite colours cancels them out and produces white (gray). I used the colour wheel all the time when printing photos in the lab I worked in. Altering th...