Thanks, that makes sense. In blend.c there is code conditional for non LAB colorspace "if(cst==iop_cs_Lab)"
I don't understand how this would be used though. Aren't all module operations in Darktable done in LAB colorspace? For example how could I get the colorize module to work in RGB colorspace? Is there something in "input color profile" to change this? Quoting Ulrich Pegelow <[email protected]>: > Am 21.04.2013 21:01, schrieb [email protected]: >> I have a question about how the blend modes operate. >> >> They do not appear to match the usual algorithms, or output from other >> editing software. For example, using the colorize module, the >> following two cases don't work as I expected: >> >> - A difference blend with plain black image, should do nothing. >> - A difference blend with a plain white image should invert the image. >> >> From looking at the code, I assume it's the clamping that's making >> the difference? > > The current implementation of the difference blend mode does not work > correctly for modules in Lab color space. Reason is that there is no > generally working definition how a difference in the a-channel or > b-channel should be translated into the output. For that reason other > software (PS) does not offer this blend mode for Lab images. darktable > does but as said before the output is mostly useless. > > Ulrich > > ------------------------------------------------------------------------------ > Precog is a next-generation analytics platform capable of advanced > analytics on semi-structured data. The platform includes APIs for building > apps and a phenomenal toolset for data science. Developers can use > our toolset for easy data analysis & visualization. Get a free account! > http://www2.precog.com/precogplatform/slashdotnewsletter > _______________________________________________ > darktable-devel mailing list > [email protected] > https://lists.sourceforge.net/lists/listinfo/darktable-devel > ------------------------------------------------------------------------------ Precog is a next-generation analytics platform capable of advanced analytics on semi-structured data. The platform includes APIs for building apps and a phenomenal toolset for data science. Developers can use our toolset for easy data analysis & visualization. Get a free account! http://www2.precog.com/precogplatform/slashdotnewsletter _______________________________________________ darktable-devel mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/darktable-devel
