Julian, On 16/06/13 18:18, Julian J. M. wrote: > I clearly don't master color management... I hope some of you can > enlighten me. > > I have an ICC profile for my monitor, created with a Pantone Huey Pro. > Actually I have one for each monitor, and darktable picks the correct > one depending on which monitor it's on. > > Main screen: > [color profile] we got a new screen profile from the _ICC_PROFILE (size: > 18660) > Secondary screen: > [color profile] colord gave us a new screen profile: > '/home/julian/.local/share/icc/GCM - Hewlett Packard - HP 2311x - > 3CQ21701N9 (2013-04-04) [15-31-56].icc' (size: 18648) > > So far so good. I know my monitors are kind of crappy ones, and that the > calibrator is not a spectrophotometer. Anyway, both monitors have a > diferent tint when no ICC profile is applied (gnome colord), and > darktable look the same on both when they are applied. > > > I've sent some pictures to print (3 different online shops), and they > resulted quite darker than what I see on screen. A lot of dark zones > detail is lost. All 3 with very similar results. Also, the exported jpgs > are darker that what I see on darktable, when I see them in the the > browser (Google Chrome). The profile I use when exporting is sRGB > perceptual.
I think you need to calibrate your printer. Not sure if your calibration device has that capability, but if it does creating an ICC profile for your printer would be a good idea. > > Now, playing with the Output Color Profile module... I see that the > screen profile is set to "system profile". If I change it to sRGB, the > image I see (darkroom) looks exactly the same as the exported JPGs. I'm > not sure what I'm changing here... Is the monitor ICC profile ignored if > I change this? Once you have a printer profile, you either need to use that when exporting jpeg in DT and ensure that your system does not use the profile when printing. Or, set the system to use you printer's profile then set the exported image to use sRGB (I'm not sure on this step, to be honest). Here is what I think happens. After demosaicing, the RAW file is converted to an internal colour space using the camera's ICC profile. The internal colours are converted using the screen's profile. When you export an image, the profile in the image is used to convert the pixel values in the image back to this internal form and then the printer's profile is used to convert this internal form back to pixel values for the printer. Every device has a gamut, which represents the limits of the colours that device can accurately display. Screen gamuts are much larger than printers, so the outputs may look different if on the screen you see colours the printer cannot reproduce. Having everything calibrated and the right profiles used everywhere should minimise the differences. Regards, Tony. -- Tony Arnold, Tel: +44 (0) 161 275 6093 Head of IT Security, Fax: +44 (0) 705 344 3082 University of Manchester, Mob: +44 (0) 773 330 0039 Manchester M13 9PL. Email: [email protected] ------------------------------------------------------------------------------ This SF.net email is sponsored by Windows: Build for Windows Store. http://p.sf.net/sfu/windows-dev2dev _______________________________________________ Darktable-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/darktable-users
