A technically simple exercise, though the point is to be able to assess the change in strength of a colour and how it impresses a mood on the overall image.
For this exercise I photographed a red tile floor - the camera suggesting a 1/5th shutter speed at F9 as the correct stop for exposure.
While the Hue does not change - the floor paint is discernably red, the saturation does indeed change, with more and less exposure, as does the relative brightness.
The brightness changes recorded show an increase in the degree of black shown, while over exposure introduces white into the over exposed images. these brightness affects combine with the affected saturation level, the more saturated being the underexposed images.
All of the redness could be affected by filtering - either post production or filtering 'in camera'.