A method of representing an amount of image color in a composite image includes the steps of generating at least one additional opacity channel for use in creating the composite image, and compositing at least one graphical object having object color and object capacity, with an image having image opacity and the image color, to create the composite image. The composite image has composite image color and composite image opacity, and the composite image color and composite image opacity are derived from one or more of the object color, the object opacity, the image color and the image opacity. An additional step includes compositing the object opacity with the additional opacity channel to create an updated opacity channel, with the updated opacity channel representing an amount of the image color remaining in the composite image following the compositing of the at least one graphical object with the image.