问题
I have an EPS file that contains c, m, y and k 4 channels. I try to use Ghostscript ps command to separate it to 4 1bit tiff images.
I don't have any idea about screening function in gs command .
Does anyone known how to adjust screening in gs command?
How to set 1 bit tiff's frequency(lpi) and angle for each separation color?
回答1:
I presume you mean you have an EPS file, not an ESP file. If so then the EPS program should not contain any halftoning information.
You can use the -c "..." -f sequence to send PostScript directly to Ghostscript, or write PostScript into a file to be processed before your EPS file.
You will find that halftone screening is covered in considerable depth in the PostScript Language Reference Manual, Section 7.4 on page 494 onwards. You can use the old setscreen (one halftone screen only), setcolorscreen (one halftone per plane, Gray, CMYK or RGB) or sethalftone which allows considerably more flexibility.
See also the -dCOLORSCREEN switch described here
来源：https://stackoverflow.com/questions/42620359/how-to-adjust-screening-frequency-and-angle-using-ghostscript