A method of adding display rendering specification information to an input image from a set of video images, the information being usable by a receiving side color rendering image processing apparatus to control the rendering of image region luminances of respective images for at least two displays of different luminance dynamic range, the method comprising: - a) showing the input image to a human operator; - b) receiving via a user interface (303, 308) descriptive data of a regime region in the input image from the human operator, the descriptive data including: firstly region selection information (F_sel()_1) to enable extraction of a region of pixels at a receiving side, which region selection information comprises at least one luminance value demarcating pixels having luminances respectively above or below it, or geometric information delineating the region of pixels, and secondly a regime descriptor (rd), which encodes a color rendering specification for that region of pixels for at least two of various receiving side video displays having different output luminance dynamic ranges, which regime descriptor (rd) comprises a parametric formulation of an intended rendering as a function of at least a display white luminance, so that a receiving side color rendering image processing apparatus can determine a final intended rendering based on an actual value of its display white luminance and the parametric formulation; - c) encoding the descriptive data including said regime descriptor (rd) into an output description data signal in a video transmission encoding signal (S') suitable for communicating video to a receiving side, such as an MPEG-family encoding, with an image of pixels derived from the input image and being encoded according to the video transmission encoding and the descriptive data being encoded as metadata. - a) showing the input image to a human operator; - b) receiving via a user interface (303, 308) descriptive data of a regime region in the input image from the human operator, the descriptive data including: firstly region selection information (F_sel()_1) to enable extraction of a region of pixels at a receiving side, which region selection information comprises at least one luminance value demarcating pixels having luminances respectively above or below it, or geometric information delineating the region of pixels, and secondly a regime descriptor (rd), which encodes a color rendering specification for that region of pixels for at least two of various receiving side video displays having different output luminance dynamic ranges, which regime descriptor (rd) comprises a parametric formulation of an intended rendering as a function of at least a display white luminance, so that a receiving side color rendering image processing apparatus can determine a final intended rendering based on an actual value of its display white luminance and the parametric formulation; - c) encoding the descriptive data including said regime descriptor (rd) into an output description data signal in a video transmission encoding signal (S') suitable for communicating video to a receiving side, such as an MPEG-family encoding, with an image of pixels derived from the input image and being encoded according to the video transmission encoding and the descriptive data being encoded as metadata.