Find a strong definite colour and choose a viewpoint so that it fills the frame. Take a sequence of pictures to include the original metered setting, half a stop brighter, one stop brighter, half a stop darker and one stop darker.
In each of these images, the aperture has been increased by half a stop so they range from overexposed to underexposed via the correct exposure. The correct exposure was measured before the start of the exercise.
It is clear that changing the exposure alters the brightness of the colour, but not the saturation. The colour remains pure, but it changes in tint, tone and shade.