Flowers under red light. Colour is the result of an object reflecting and absorbing different parts of the visible (light) spectrum. Only reflected light contributes to an object's colour. When red light is present, objects that reflect this wavelength of light will appear red. This is the case for the red, white and purple flowers. However, the green foliage absorbs the red light and appears black. See A200/379-382 for images of flowers under different coloured lights.