Method for color correction for multi-color printing plate pictures

A method for color correction in the process for reproducing a picture in which color separation picture signals obtained by photoelectrically scanning an original picture are converted into picture signals which correspond to four printing color inks including a black ink therein to produce respective reproduction pictures for plate making corresponding to each of the color inks. A picture signal which corresponds to a black ink is produced according to gray color components obtained from B, G and R signals of the original picture, and according to chromatic color components obtained by subtracting neutral color components from said B, G and R signals. Color separation picture signals corresponding to other color inks, and deficiency in reproduction density of the black ink to be used in a black print is corrected by said other three color inks.