Our invention answers the need for images to be compared and analyzed without being influenced by changes in the ambient light. It grants the user a means of quantifying the color in the lesion, in order to determine the degree of change which has occurred in the lesion, and whether the changes are sufficiently significant to indicate undesirable biological changes. The tool allows evaluation of the degree of response to treatment, or of the degree of spontaneous healing of the lesion and can be considered a novel medical diagnostic technology.