Hi Marti, even with that parameter set, the colors are different. Absolute colorimetric was just one Intent I tried, but it was the same problem with all the other intents. There is always much more red in the lcms-version.
Here is a comparison with INTENT_RELATIVE_COLORIMETRIC. https://www.dropbox.com/s/nsgfp2c9cab6g6w/pslcms.jpg Might that be related to the whitepoint? Regards Andreas Am 28.09.2012 um 00:13 schrieb Marti Maria <marti.ma...@littlecms.com>: > > Hi, > > Just add cmsSetAdaptationState(1.0) at the begin of your code to get same > results as photoshop. BTW, are you using recent versions of lcms?... that > should be the default right now. > > The reason why this fix the issue is somehow complicated. ICC even published > a note on that > http://color.org/ICC_white_paper_6_v2_and_v4_display_profile_differences.pdf > > I would recommend you to avoid absolute colorimetric intent whatever > possible. It is only useful for calculations, and may people gets confused > because the color cast due to lack of chromatic adaptation. Perceptual or > relative colorimetric are way more intuitive. > > Regards > Marti. > > El 27/09/2012 22:11, Andreas Rettig escribió: >> Thanks a lot for help! >> >> When I convert with Photoshop to sRGB / Absolute Colorimetric, I get >> different colors than I get from lcms. >> Example: At xy(268, 190) I get RGB(0,163,77) in Photoshop, but RGB(77, 164, >> 1) in lcms. >> Both images are opened in Photoshop for picking the colors. >> >> I noticed the color shifts in the border areas, too, but the difference is >> much bigger there than the difference generated by different positions on >> the screen. >> >> Code is pretty simple: >> >> QImage* image = new QImage("/Users/ar/Desktop/basICColor_CM-Ampel.jpeg"); >> cmsHPROFILE hInProfile, hOutProfile; >> cmsHTRANSFORM hTransform; >> hInProfile = cmsOpenProfileFromFile("/Users/ar/Desktop/ampel.icc", "r"); >> hOutProfile = >> cmsOpenProfileFromFile("/System/Library/ColorSync/Profiles/sRGB >> Profile.icc", "r"); >> hTransform = cmsCreateTransform(hInProfile, >> TYPE_BGR_8, >> hOutProfile, >> TYPE_BGR_8, >> INTENT_ABSOLUTE_COLORIMETRIC, 0); >> cmsCloseProfile(hInProfile); >> cmsCloseProfile(hOutProfile); >> uchar *rgbOutTemp = new uchar[(image->width() * image->height()) * 3]; >> uchar *rgbInTemp = new uchar[(image->width() * image->height()) * 3]; >> int j = 0; >> for(int y = 0; y < image->height(); y++){ >> for(int x = 0; x < image->width(); x++){ >> QColor col = image->pixel(x, y); >> rgbInTemp[j] = col.blue(); >> rgbInTemp[j + 1] = col.green(); >> rgbInTemp[j + 2] = col.red(); >> j += 3; >> } >> } >> >> cmsDoTransform(hTransform,rgbInTemp,rgbOutTemp,image->width()*image->height()); >> QImage* imout = new QImage(image->width(), image->height(), >> QImage::Format_RGB32); >> int s = 0; >> for(int h = 0; h < imout->height(); h++){ >> for(int w = 0; w < imout->width(); w++){ >> QColor color(rgbOutTemp[s], rgbOutTemp[s+1], rgbOutTemp[s+2]); >> imout->setPixel(w, h, color.rgb()); >> s+=3; >> } >> } >> ui->label->setPixmap(QPixmap::fromImage(*imout)); >> imout->save("/Users/ar/Desktop/saved.jpg","JPG",100); >> >> Regards >> Andreas >> >> Am 27.09.2012 um 20:31 schrieb Marti Maria <marti.ma...@littlecms.com>: >> >>> >>> Hi Andreas, >>> >>> I have tested your image with PS CS4 and get 1 digital count of deviation >>> of PhotoShop, which is due to the way different CMM do rounding. I can see >>> no differences in color. >>> >>> Could you please detail the steps you follow to get different results? >>> >>> Thanks >>> Marti. >>> >>> >>> El 27/09/2012 19:37, Andreas Rettig escribió: >>>> Hello, >>>> >>>> I'm trying to make my first steps with LCMS and build a very simple >>>> application to get familiar with everything. >>>> All I want to do is transform a RGB-Jpeg from a special input profile to >>>> sRGB and produce the same results I get when I do exactly the same in >>>> Photoshop. >>>> >>>> I'm using that image for testing with its embedded ICC profile as Input >>>> profile: >>>> >>>> http://www.colormanagement.org/download_files/basICColor_CM-Ampel.jpg >>>> >>>> Then I do a simple transformation from ampel.icc -> sRGB.icc, with >>>> different intents. >>>> The results are always a little different from what I can produce in >>>> Photoshop (using the same profiles and the same intent). >>>> >>>> The traffic light is green after the transformation, which shows me that >>>> it roughly works - but I expect to get exactly the same result. >>>> >>>> The same happens in Gimp - it's always a little different from what I get >>>> through lcms (I saved the results to a file and checked RGB-Values). >>>> Especially these grids at the borders have very different colors. >>>> >>>> Sourcecode is more or less from the examples, nothing special. Profiles >>>> are the exactly the same in lcms and Photoshop. >>>> >>>> Regards >>>> Andreas >>>> >>>> >>>> ------------------------------------------------------------------------------ >>>> Everyone hates slow websites. So do we. >>>> Make your web apps faster with AppDynamics >>>> Download AppDynamics Lite for free today: >>>> http://ad.doubleclick.net/clk;258768047;13503038;j? >>>> http://info.appdynamics.com/FreeJavaPerformanceDownload.html >>>> >>>> >>>> _______________________________________________ >>>> Lcms-user mailing list >>>> Lcms-user@lists.sourceforge.net >>>> https://lists.sourceforge.net/lists/listinfo/lcms-user >>> >> > > >
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