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Cody3331749

: Change RGB to CMYK colour in PDF I have a PDF produced by matplotlib/python. Since matplotlib does not support CMYK, I used blue (0 0 1) colour for the reference where I want to have CMYK

@Cody3331749

Posted in: #Postscript

I have a PDF produced by matplotlib/python. Since matplotlib does not support CMYK, I used blue (0 0 1) colour for the reference where I want to have CMYK colour. My plan is to change that colour to CMYK colour manually using the text editor.

I have identified that the part

w 0 0 1 RG


specifies blue (0 0 1) colour. I would like to manually replace this part in a way to have CMYK colour. Is that possible to do?

[I was already instructed that it might be better to use a RGB color like (0.1234 0.1234 0.99999) so that I have enough space to over-write with CMYK specification and white space and not affect the byte count anywhere.]

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@Alves566

I got the answer elsewhere. If anyone else would be interested, it should be something like that

1 0 0.047 0.722 K

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@Jessie844

There is not only one way RGB to CMYK. That depends on a color profile.

This color profile needs to take into account what kind of paper and ink the user will be using. And this color profile makes a series of conversions using some kind of mathematical matrixes.

In my opinion you should leave the values as RGB and let the user's printer configuration convert the file to whatever they need.

You only need to make a CMYK output if you are sending a file to a comercial offset print, but it would be better to have a human designer supervising this colors.

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