Thank you William for your answer. Actually I saw in the release notes ( http://poppler.freedesktop.org/releases.html ) what you mention. The 0.17.2 introduces the optimization you are talking about: poppler-0.17.2.tar.gz <http://poppler.freedesktop.org/poppler-0.17.2.tar.gz> (Mon Aug 15, 2011): PSOutputDev: Make level1sep, level2sep and level3sep write gray instead of rgb for gray images
Yes it makes a problem for me, and it would be great to have this feature. How can I proceed to have it? I'm a java developer, not comfortable in C/C++... not sure I would be able to make a pull-request in git. 2015-02-04 17:44 GMT+01:00 William Bader <[email protected]>: > I think that the cause is a patch that I submitted in May 2011 around the > time of poppler 0.17.0. > > Search for isGray in poppler/PSOutputDev.cc > > I use pdftops to make postscript files that will be printed on a newpaper > press. > > My application was being sent PDFs with embedded logos that looked gray > but were actually in RGB color space, and they were not getting separated > correctly on color pages. > > I added a check in PSOutputDev that if every pixel of a RGB bitmap was > equal R, G, B, it will be written as a grayscale bitmap, which fixed my > separation problems and made the files smaller. > > If that makes a problem for you, it should be possible to add a command > line option to control the RGB to grayscale conversion, maybe similar to > some of the distiller options in ghostscript > http://ghostscript.com/doc/current/Ps2pdf.htm > > William > > ------------------------------ > Date: Wed, 4 Feb 2015 16:18:59 +0100 > From: [email protected] > To: [email protected] > Subject: [poppler] pdftops : issue with colorspaces with some printers > (gray vs rgb) > > > Hi everyone, > > > My name is Benjamin and I am french. > > > I'm new on this mailing list :) > > > I come to you for a question or maybe for a feature request (at this > stage, I'm not sure). > > > Please look at this pdf (dropbox: > https://www.dropbox.com/s/yoj6h3o4irnlgun/source.pdf?dl=0 > ) <https://www.dropbox.com/s/yoj6h3o4irnlgun/source.pdf?dl=0> > > > There are two monochrome images (in DeviceRGB in the pdf). > > > After executing 'pdftops', the images are cut in half, with the top part > in DeviceRGB and the bottom in DeviceGray. This causes colorimetric issues > on some of my printers (most of them in fact). > > > Is it possible to preserve DeviceRGB by executing pdftops? I did not > manage to achieve it with the few available options provided by pdftops..... > > Or would it be possible to have a new option in poppler (pdftops in my > case) to preserve colorspaces, and to not optimize the monochrome images in > DeviceGray? > > > Thank you in advance, > > > Benjamin. > > > > > > _______________________________________________ poppler mailing list > [email protected] > http://lists.freedesktop.org/mailman/listinfo/poppler > -- *Benjamin Lefevre* Senior Software Engineer / iWays & iRender *Email *[email protected] *Address *37-39 rue de Beauce - 78500 Sartrouville (France) *Phone *+33 (0)1 30 86 80 43 [image: PHOTOBOX]
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