Hi again Marti, Gerhard, others... I will try to be more clear in my wording and objectives:
Objective: I want to get a fair estimation of the Lab colours from the ICC profile, when using relative colorimetric conversion. Current results / conclusions: a. After applying the output profile, the Lab values in Photoshop (or using lcms utilities) do not match the measured Lab values well. b. If I use absolute colorimetry during the transform, the whitepoint Lab display valus 'improve'. Some other colours are way off, however... c. I don't *wan*t to use absolute colorimetry as it changes the RGB values too much. For instance white (Lab 100,0,0) is trnaformed to 229,246,255. If I print this, I don't get paper white anymore, yet my paper is becoming even more blue :( Some thoughts: The ICC profile *knows* about the actual colour <> RGB relation (it is the major function of the profile). Therefore, I would think, it should be able to specify, approximately, using its 3D LUT, what the Lab values will be when I print using a particular RGB combination. However, the match is quite poor. Is this a bit more clear? Can you help? TIA and greetings, Auke > > Hi, > > Ok, this may be due to white point mismatch. AdobeRGB is operating under > D65, so > I wonder if this is the case. You could try that: > > - with icctrans, convert some Lab values using abs. colorimetric to the > printer profile. > > icctrans -t3 -i*Lab -o printer_profile.icc > > This will give you some RGB values. Create a image with such values. Print > the image TURNING ALL COLOR MANAGEMENT OFF! Measure the > patch. If the dE is not good, then the problem is in the output profile. > Besides, > this is a photosmart printer, a dE of 3-4 is actually not so bad if you > are > using a generic profile. > > Regards, > Marti Maria > The little cms project > http://www.littlecms.com > ------------------------------------------------------- SF email is sponsored by - The IT Product Guide Read honest & candid reviews on hundreds of IT Products from real users. Discover which products truly live up to the hype. Start reading now. http://productguide.itmanagersjournal.com/ _______________________________________________ Lcms-user mailing list [EMAIL PROTECTED] https://lists.sourceforge.net/lists/listinfo/lcms-user
