Sorting colors is the sort of thing that you never really think about until you need to do it. Sorting a bunch of items by their color is useful in a number of applications, but the simplest is just to display items to the user in a more controlled manner. As it happens sorting with colors is a much more complex topic than I originally thought and required digging into quite a bit more maths than I expected.
Incidentally, there is a whole world of color maths that I didn't know existed until I started looking into this. It was worth learning about though.
To start with, I created a little Color class so that I could have a standard way of storing a color. This just takes the red, green and blue values for a color and allows a simple way of accessing those values.