RGB to CMYK colorspace not available in Libre

asked 2017-08-26 13:30:13 +0200

Googly Googly gravatar image

updated 2017-08-26 16:48:19 +0200

I have created TEXT files in Libre. Around 4000 pages in all. A lot of efforts put in by many scholars. Now, we have submitted the PDF files for printing to a printing press. The press wants the files to be in CMYK colorspace. We did not know this issue. When the pdf is created, the output shows RGB colorspace. Librewriter in Tools>Options>Colors shows CMYK. But the values of CMYK which appear in Writer do not appear in PDF. PDF shows mixed values. My pdf files should have the Magenta text as C-0, M-100, Y-0, K-0 and Black text as C-0, M-0, Y-0, K-100. That is how it is set in Writer. But, PDF doesn't contain those values. Already tried following things but the solution is not coming. (Stating the tried solutions to avoid repeated suggestions and denials)

  • Tried Gimp, Scribus, Inkscape - When a pdf is opened there, either the text gets disturbed or there is no conversion. We have the files in Complex Script Devanagari (Hindi) and not in English.
  • The is some terminal command to convert from RGB To CMYK. It runs. But, the desired output namely - C0M100Y0K0 and CMY0K100 is not coming. The command should have something like which converts a particular RGB to a particular CMYK. It only changes the RGB to CMYK, but the color output is yet the mixture.
  • Open the File in the Photoshop CS2 and used the conversion tools US Uncoated SWOP etc. But, the problem persists.
  • LIbre in Windows creates the CMYK of nearly desired degree. But, the Devagari text gets distorted to some extent, which is unacceptable.
  • Submitted the files for Online conversion. It does change the RGB to CMYK but the mixture not set right. Lacks desired CMYK percentage.
  • In Windows, PDF995 printer when used with LIBRE converts the K color correctly but doesn't convert M. Moreover, Libre with Windows is not as good as it is in Linux. Quality of text is to be sacrificed.

Badly caught in the complex situation. Shifting entire text and all the files to Latex, InDesign, etc is a huge task. If someone can help me out of this mess, nothing like that. The issue has killed so much of valuable time to figure out the problem and find out any solution. Feeling like giving up Libre and Linux for future. The solution should convert odt to pdf or pdf to pdf with desired color space.

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Doesn't @oweng's answer to this question help? Or does your second list item refer to that?

Mike Kaganski gravatar imageMike Kaganski ( 2017-08-26 13:52:08 +0200 )edit

Try out pdf24. They say you can save as CMYK pdf. pdf24 creates a virtual printer, there are lots of customizing features.

Grantler gravatar imageGrantler ( 2017-08-26 14:52:40 +0200 )edit

@Mike Kagaskri -- This option of print text in black converts Magenta to black. However, the black is C0M0Y0K100. Halfway through. Yet the full solution is awaited. Nonetheless, thanks for taking time to comment.

Googly Googly gravatar imageGoogly Googly ( 2017-08-26 16:40:51 +0200 )edit

@Grantler -- pdf24 is meant for Windows. I don't find any link or mention of it for Linux/Ubuntu. Our files are created in Libre on Ubuntu. When Libre is used in Windows and files are opened there, the text shows some distortion, overlapping etc for Devanagari Script. That goes beyond acceptable limits. Hence, running Libre in Windows is out of question. Thanks for the suggestion.

Googly Googly gravatar imageGoogly Googly ( 2017-08-26 16:48:09 +0200 )edit

Do you pay attention to what you are told? I referred to oweng's answer.

Mike Kaganski gravatar imageMike Kaganski ( 2017-08-26 17:06:01 +0200 )edit

@Mike Kagasnki -- I tried Oweng's answer now. The output it gives was tested in Photoshop and Gimp. There is no desired color combination like for Magenta - C-0, M-100, Y-0, K-0 and for Black text- C-0, M-0, Y-0, K-100

Googly Googly gravatar imageGoogly Googly ( 2017-08-26 18:37:40 +0200 )edit

That might mean that RGB magenta in LO does not map to C-0, M-100, Y-0, K-0... Unfortunately, LO internally only uses RGB (which is mentioned in documentation). GhostScript does not have color replacement capabilities itself. I wonder if there is another tool that has.

(waiting for another permutation of my name ;) )

Mike Kaganski gravatar imageMike Kaganski ( 2017-08-26 19:51:16 +0200 )edit

@Mike Kaganski (Sorry for the name confusion.) Very sorry to know that the solution is nor near. However, few brilliant guys have figured out some solution. I fail to understand the technical jargon. Pl see if something can be done.

Link-1 https://stackoverflow.com/questions/2...

Link-2 https://stackoverflow.com/questions/1...

Googly Googly gravatar imageGoogly Googly ( 2017-08-26 20:00:23 +0200 )edit

According to this page, your PDF file can be converted to CMYK using either Adobe Acrobat Pro or Foxit PDF Editor.

librebel gravatar imagelibrebel ( 2017-08-26 20:06:07 +0200 )edit

@Googly Googly: citing the first link, pdflatex automatically does that (with the xcolor package) for all fonts and drawn objects - isn't that what you actually need? The rest of it was discussion about how to proceed with embedded images that were also in RGB.

@librebel: the problem is not with converting to CMYK, but also with ensuring that black is 100% black and magenta is 100% magenta in resulting converted file (which isn't guaranteed when converted from RGB IIUC).

Mike Kaganski gravatar imageMike Kaganski ( 2017-08-26 20:38:36 +0200 )edit