To allow a better coordination between an image creation artist such as a movie director of photography and the final viewer, via a receiving-side display and its corresponding image processing, a method of adding display rendering specification information to an input image signal (I) comprises determining descriptive data (D) that includes at least identification information for at least one luminance regime subset of pixels of an input image; and encoding the descriptive data (D) into an output description data signal (DDO), relatable to an output image signal (O) based upon an input image signal (I), of the descriptive data (D) in a technical format standardized to be intended for use by a receiving-side display to control its image processing for changing the color properties of its rendered images.