1. A method of modifying color data of at least one rendered image, the method comprising: receiving sample points associated with a computer graphics scene, wherein at least one sample point includes first color data including an unilluminated color of a scene entity, second color data including a first light source color contribution, and third color data including a second light source color contribution; modifying the first color data for the at least one sample point; modifying the second color data for the at least one sample point independently of modifying the first color data; modifying the third color data for the at least one sample point independently of modifying the first color data; and determining an output color for the at least one sample point based on at least the modified first color data, the modified second color data, and the modified third color data; wherein the first light source color contribution comprises a color contribution from one or more light-to-scene entity relationships; wherein each light-to-scene entity relationship included in the one or more light-to-scene entity relationships defines a color contribution of one light source on one scene entity; wherein the second light source color contribution comprises a color contribution of a group of light sources, wherein the first light source color contribution is different from the second light source color contribution.