<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0//EN" "http://www.w3.org/TR/REC-html40/strict.dtd"> <html><head><meta name="qrichtext" content="1" /><style type="text/css"> p, li { white-space: pre-wrap; } </style></head><body style=" font-family:'DejaVu Sans'; font-size:12pt; font-weight:400; font-style:normal;"> On Tuesday, February 08, 2011 09:43:08 AM Till Kamppeter wrote: > On 02/08/2011 06:04 PM, Kai-Uwe Behrmann wrote: > > Great news. A ICC enabled pdftoraster filter is a huge step forward for > > colour managed printing. Many thanks for your work on that. > > Also thanks to Otani-san who wrote this filter and also many other PDF > filters. > > >> Color management experts from OpenICC, WDYT about this color > >> management effort? Is this already a step forward? Is it at least the > >> correct effort for > > > > Yes, such a pdftoraster filter is a pre condition for any main stream > > colour management on Linux. > > > >> consumer-level printing? What needs to be added to support pro and > >> prosumer printing? > > > > I think consumer lever printing with canned profiles might be already > > served to some degree by your announced changes and CUPS capabilities. > > Vendors can bundle their drivers, PPDs and ICC profiles to deliver a out > > of the box improvement. The same for administrators to setup colour > > managed queues. > > > > > > The recent weeks we discussed here on OpenICC in length about user side > > colour managed printing. As PDF, CUPS, Poppler/Ghostscript and CPD are > > rather complex, we had many thoughts about it. The question was more or > > less, how can users opt-out of colour management > > for calibration. And how to assign own profiles to a print job to > > override the PPD configured profiles. As well passing rendering intent > > and black point compensation options is yet unclear to us. > > Otani-san, if one has a print queue with installed ICC profiles, is > there an easy way to turn off ICC color management with your > pdftoraster? This way advanced users could do a calibration to create > their own ICC profiles. Also can one override the PPD's ICC profiles to > use user-supplied ones (for example embedded in the pDF job)? What about > sending rendering intent and black point compensation along with a job? > Can you, if needed, add options to the pdftoraster and/or the > possibility to read info/data embedded in the PDF jobs? It appeaers that at present poppler does not support either rendering intent or BPC. At least I don't find anything on the poppler email list about this since May 2009 when it was stated that this was a very complex problem and had not been addressed yet. "As Leonard said INTENT can come from several places, it's not so <pre style=" margin-top:0px; margin-bottom:0px; margin-left:0px; margin-right:0px; -qt-block-indent:0; text-indent:0px; -qt-user-state:0;">simple to handle INTENT correctly. We have to check if current INTENT</pre> <pre style=" margin-top:0px; margin-bottom:0px; margin-left:0px; margin-right:0px; -qt-block-indent:0; text-indent:0px; -qt-user-state:0;">is changed and recreate transform if needed.</pre> <pre style=" margin-top:0px; margin-bottom:12px; margin-left:0px; margin-right:0px; -qt-block-indent:0; text-indent:0px; -qt-user-state:0;">This is why I didn't support INTENT this time."</pre> <pre style="-qt-paragraph-type:empty; margin-top:0px; margin-bottom:12px; margin-left:0px; margin-right:0px; -qt-block-indent:0; text-indent:0px; -qt-user-state:0; font-family:'Courier New,courier';"></pre> <pre style=" margin-top:0px; margin-bottom:12px; margin-left:0px; margin-right:0px; -qt-block-indent:0; text-indent:0px; -qt-user-state:0;">I have not been able to locate any additional threads on the email list about implementing </pre> <pre style=" margin-top:0px; margin-bottom:12px; margin-left:0px; margin-right:0px; -qt-block-indent:0; text-indent:0px; -qt-user-state:0;">rendering intent. I also had a quick look at the code and I didn't find anything that sets the </pre> <pre style=" margin-top:0px; margin-bottom:12px; margin-left:0px; margin-right:0px; -qt-block-indent:0; text-indent:0px; -qt-user-state:0;">rendering intent for CM other than two places where relative colormetric is hard coded in </pre> <pre style=" margin-top:0px; margin-bottom:12px; margin-left:0px; margin-right:0px; -qt-block-indent:0; text-indent:0px; -qt-user-state:0;">the cmsCreateTransform call. This appears to be unchanged since 2009. So it appears </pre> <pre style=" margin-top:0px; margin-bottom:12px; margin-left:0px; margin-right:0px; -qt-block-indent:0; text-indent:0px; -qt-user-state:0;">that poppler currently always does relative colormetric intent regardless of what intents </pre> <pre style=" margin-top:0px; margin-bottom:12px; margin-left:0px; margin-right:0px; -qt-block-indent:0; text-indent:0px; -qt-user-state:0;">in coded into the PDF file for it's objects. I can live with this for initial testing of the </pre> <pre style=" margin-top:0px; margin-bottom:12px; margin-left:0px; margin-right:0px; -qt-block-indent:0; text-indent:0px; -qt-user-state:0;">workflow but it does need to be fixed before this is considered production. </pre> > > > I tried to summarise some of the issues without giving it a proper > > architectural shape yet. However these notes might help to understand > > where the discussion stands: > > https://www.oyranos.org/wiki/index.php?title=Device_Settings#Printing > > For the "wget http://localhost:631/profiles/sRGB.icc" problem, there is > an STR on > > http://www.cups.org/str.php?L2896 > > Please add your comments. > > A possibility to send user-supplied profiles along with a job could be > embedding the profile in the PDF job. The Common Printing Dialog would > be the best place to do this. pdftoraster would need a feature to read > out such profiles and use them instead of the PPD-specified ones. > > You should mention on the Wiki page that Poppler supports ICC color > management, too. > > Till > _______________________________________________ > openicc mailing list > openicc@lists.freedesktop.org > http://lists.freedesktop.org/mailman/listinfo/openicc </body></html>