Setting the scene
In this tutorial, we are going to be investigating the scene depicted in the image below. While it may look quite normal (albeit a bit contrived), the scene is particularly interesting for us because it was captured with a special process that allowed the light at different wavelengths to be measured separately. Recall that our vision is sensitive to wavelengths between about 400 and 700 nanometres (nm) within the broader electromagnetic spectrum.
Note that we are going to be investigating the scene as if you were standing in the room looking at it, and not how the scene is being reproduced on the computer monitor you are using.
These images were captured by David Brainard at the University of Pennsylvania.
We will start by considering the spectral composition of the scene; that is, the spectrum that underlies each pixel in the image. Then, we will look at how these spectra affect the cone photoreceptors in the retina. We will then move into a more perceptual representation of colour, before considering some of the consequences of anomalous photoreceptors ('colour blindness').
When you are ready, you can move on to The spectral composition of the scene.