A colored original which is painted with a plurality of predetermined colors is scanned along each of a plurality of line paths each of which can be divided into one or more colored line segments. Encoders are provided to characterize each of the line segments by a corresponding first code representing the color of the segment and a second code representing the run length of the segment. The first and second codes are sequentially recorded in a data file memory. The recorded information is repeatedly retrieved from the memory and transferred to a shift register. Line segments carrying the same color within each line path are detected by comparing the corresponding first code with a specified code. The second code is sequentially decoded into run lengths which are accumulated to measure the position of color transitions relative to the colored original. A video signal is generated upon occurrence of coincidence between the first code and the specified code. A photographic film is scanned by a light beam modulated with the video signal to develop an image carrying the detected color on a specified portion of the film in correspondence with the specified code. The codes to be specified are sequentially changed to detect the line segments of different colors in a predetermined sequence within the period of the scanning. In synchronism with the code change, the shift register is shifted to recirculate the data.