Hi Francisco, Ulrich's advice seems right on!
In the newer NEF file I'm still not seeing areas of reds with low enough luminosity to trigger these artifacts. It may just be that the X-Trans image by a particularly fortuitous chance recorded such saturated dark reds, but that's a hard to replicate situation? Best, Dan On Mon, Jan 5, 2015, at 03:10 PM, Ulrich Pegelow wrote: > There have already been some very valid remarks on this topic. It's > obvious that your specific use of the tone curve can give some issues at > the "darker" end. > > Eventually this is strongly linked to the occurence of "unbounded" > colors. You can read here > http://www.darktable.org/usermanual/ch03s02s10.html.php to learn more > about that topic. > > A possible solution is to use the gamut clipping feature in the input > profile module. You need to experiment a bit to find out which clipping > profile leaves you best color dynamic while preventing artifacts. I > found AdobeRGB to be a good choice in your example image. > > Best wishes > > Ulrich > > Am 05.01.2015 um 00:22 schrieb Francisco Cribari: > > My second camera is a Fuji X100S, which has an X-Trans sensor. I am > > getting color artifacts in several images when I raise the lower end of > > the tone curve. The problem does NOT happen with my Nikon D800 RAW > > images, only with X-Trans RAW images. I would also like to point out > > that it is common to raise the lower end of tone curve and to lower its > > upper end. This is done to give the image a "vintage/classic" look. See, > > e.g., > > > > https://photographylife.com/that-classic-vintage-look > > > > For some reason, that tends to cause color artifacts in X-Trans RAW > > images processed using Darktable. > > > > Here is an example: > > > > RAW (.RAF) file: https://dl.dropboxusercontent.com/u/2171814/_FFX7093.RAF > > > > XMP file: https://dl.dropboxusercontent.com/u/2171814/_FFX7093_01.RAF.xmp > > > > Zoom in the image and take a look at the man's shirt (near his right > > arm). (I have already reported another case in this mailing mailing list.) > > > > I run DT version 1.6.1+30~g6b508d0 on an Ubuntu notebook. Any > > suggestions? Thank you. Francisco > > > > ------------------------------------------------------------------------------ > Dive into the World of Parallel Programming! The Go Parallel Website, > sponsored by Intel and developed in partnership with Slashdot Media, is > your > hub for all things parallel software development, from weekly thought > leadership blogs to news, videos, case studies, tutorials and more. Take > a > look and join the conversation now. http://goparallel.sourceforge.net > _______________________________________________ > Darktable-users mailing list > Darktable-users@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/darktable-users ------------------------------------------------------------------------------ Dive into the World of Parallel Programming! The Go Parallel Website, sponsored by Intel and developed in partnership with Slashdot Media, is your hub for all things parallel software development, from weekly thought leadership blogs to news, videos, case studies, tutorials and more. Take a look and join the conversation now. http://goparallel.sourceforge.net _______________________________________________ Darktable-users mailing list Darktable-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/darktable-users
