Conclusion

Different colours do not behave uniformly.

Colour, light and the visible spectrum are one and the same; energy bearing the specific characteristics to which our eyes are sensitive. When all the characteristics to which we are sensitive present themselves simultaneously, we perceive them as a singular white light. As we subtract from that set of characteristics, that is to reduce the number of wavelengths present at one time and place, we perceive the energy as colour[s] relative to the specific wave lengths present.

The fact that each colour is our perception of energy at a specific wavelength, means that a given colour's behaviour is contingent on the physical properties of its corresponding wavelength. As a rainbow illustrates, energy of a different wavelength not only manifests as a different colour but it does so, quite literally, in a different location.

Now that we know why colours act differently, let's get over it by getting on with the colouring. The next unit will introduce us to primary colours and how they are not always the same thing. Quelle surprise.