A method for virtually painting an image, the method comprising providing an image having a plurality of image pixel units, generating luminosity values based on color data (e.g., RGB triplets and LAB triplets) from the image pixel units, receiving a selection of one of the image pixel units, and setting a reference luminosity value based at least in part on a luminosity value of the selected image pixel unit (corresponding to a desired midpoint brightness). The method also comprises receiving a selection of a new color for virtually painting the image, calculating luminosity differences between the reference luminosity value and the luminosity values of the image pixel units, and generating and displaying overlay pixel units as an overlay with the image based on the calculated luminosity differences and the selected new color.