Abstract: A method and apparatus for producing color separations for single color printing in electronic reproduction, for example in textile, decorative, or packaging printing. A colored master is optoelectronically scanned point-by-point and line-by-line to obtain color signals. Color recognition signals which identify the different colors of the master during scanning are produced from the color signals. Further corrected color separation signals are obtained from the color signals. The corrected color separation signals are controlled by selected color recognition signals representing selected colors of the master. The color separation signals are switched on by the color recognition signals when the corresponding colors in the master are identified, and are switched off when the colors are not present. At least two switched on color separation signals form a recording signal which controls the recording of the color separations for the different colors of the master.

Abstract: A method for converting digital chrominance signals of a cartesian color coordinate system into digital color signals and saturation signals of a polar color coordinate system and including a transformation circuit for the transformation from cartesian to polar coordinates.

Abstract: An apparatus and a method for the recognition of colors on a colored image illuminated with a light source of a known spectrum composition, wherein the intensities of three primary colors are measured opto-electronically as color components, which represent the spatial co-ordinates of the color locations in a color space. Prior to color recognition the color components of at least one characteristic test point in each color or color region, which is to be recognized, are measured and noted. The test color components represent the corresponding test color locations in the color space. An identification symbol is assigned to each color component triplet of the test points and noted too.