Date: Wed, 11 May 2005 13:37:04 +0200 (CEST) From: Kai-Uwe Behrmann <[EMAIL PROTECTED]>
a question about colour clipping. What I am looking for is a way how to not going over Lab to avoid colour clipping. Speed is a major concern. One problem we run into (in CinePaint) is colour clipping during displaying. A oversaturated channel is not weighted against the other channels, even if the information is available. I put a small comparision together: <http://www.behrmann.name/index.php?option=com_content&task=view&id=35&Itemid=73> Clipping is something that really bothers me, too. That's why I rewrote a lot of code in (my own version of) dcraw to get around it. My own favorite method is to perform operations in HSL space rather than RGB/CMY wherever possible. Contrast stretching is one such operation. While the effects of doing it in HSL space are different from what happens in RGB space, I find the effect more natural -- the lightness is stretched without hue or saturation shifts. If you do the saturation boost with an S curve, you'll find the results are very pleasing. All of the "open sauce" color corrections in Gutenprint are performed in HSL space. Even N-color generation is currently performed in HSV (or really HV -- all gray component is removed prior to the operation, and then added back at the end) space. -- Robert Krawitz <[EMAIL PROTECTED]> Tall Clubs International -- http://www.tall.org/ or 1-888-IM-TALL-2 Member of the League for Programming Freedom -- mail [EMAIL PROTECTED] Project lead for Gimp Print -- http://gimp-print.sourceforge.net "Linux doesn't dictate how I work, I dictate how Linux works." --Eric Crampton ------------------------------------------------------- This SF.Net email is sponsored by Oracle Space Sweepstakes Want to be the first software developer in space? Enter now for the Oracle Space Sweepstakes! http://ads.osdn.com/?ad_id=7393&alloc_id=16281&op=click _______________________________________________ Lcms-user mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/lcms-user
