Abstract: A method of generating a recording beam control function for reproducing an original colored image in which a record medium is exposed to a recording beam of radiation under the control of the control function comprises (a) generating a proof (7) from the original image; (b) generating a first recording beam control function (4) at least partly from the original image using a different reproductive process (2,3); (c) comparing the color of one or more selected areas of the proof (7A,7B) with the color of the corresponding area or areas defined by the first control function; and, (d) modifying the first control function in response to the result of the comparison step to generate a second control function (6) adapted to minimize differences in color between the proof and the reproduced image.