data in the image area 1 are different from the data as in fig1 namely brightness data are stored in the g plane of another area of the image memory 2 in a line density of 400 dpi as monochromatic data the brightness data are transferred to the image area 1 in the same line density color code in the color code memory 8 is provided as data for coloring the monochromatic image according to the program of the workstation engine 9 although the subsequent operation of the color filing device 16 is the same as that in fig1 processing for density restoring in the color printing device 27 is different namely the output of the lut memory 22 is color data and the input to the image density restoring section 24 is only data for g plane therefore the output from the image density restoring section 24 is only density data for g plane which are brightness data as shown in fig9 the rgb density restoring section 28 modulates color in amplitude data multivalued data of 6 bits for each of rgb in this embodiment equally for each of rgb based on the brightness data 6 bits of g and then outputs rgb density data to the color printing section 26 if data value of g plane i e factor for brightness modilation is k and data obtained by brightness modulation of rgb are r 39 g 39 and b 39 the following equations are provided it goes without saying that in the embodiments as described above printing of only normal.