Convert PDF to CMYK but ignore black?

问题

I am converting an RGB PDF to CMYK using the following command:

/usr/local/bin/gs -dSAFER -dBATCH -dNOPAUSE -dNOCACHE -sDEVICE=pdfwrite \ 
-sColorConversionStrategy=CMYK -sColorConversionStrategyForImages=CMYK \
-dProcessColorModel=/DeviceCMYK -dEncodeColorImages=false \
-dEncodeGrayImages=false -dEncodeMonoImages=false -sOutputFile=CMYK.PDF RGB.PDF

The resulting file is 100% CMYK, however anything that was 100% black in the RGB PDF is now:

C: 72%
M: 68%
Y: 67%
K: 89%

The result is that black is a slightly dark grey when really it should be black.

Is there anything I need to add to this command to ensure black remains as black during the conversion?

回答1:

With the current version of pdfwrite you are restricted to the colour conversions in the software, and there is nothign you can do about this.

The colour management is undergoing serious revision, and the next release should make it possible to deal with this.

来源：https://stackoverflow.com/questions/21751887/convert-pdf-to-cmyk-but-ignore-black