To allow a better coordination between an image creation artist such as a movie director of photography and the final viewer (via the display and its built-in image processing), we describe method of adding image defining information to an input image signal (I), comprising: —showing the input image (I) to a human operator; receiving via a user interface (303, 308) descriptive data (D) from the human operator, the descriptive data (D) including at least luminance values and/or geometrical shape information on the one hand, and a regime descriptor (rd) on the other hand; encoding into an output description data signal (DDO), relatable to an output image signal (O) based upon the input image signal (I), of the descriptive data (D) in a technical format standardized to be intended for use by a receiving display to control its image processing for changing the color properties of its rendered images.