At Sun, 13 Oct 2013 10:04:16 +0200, Max Killer wrote: > Hello, > > for B&W images you can also use the channel mixer, which gives you > greater control in my opinion. > > But out of curiosity, why would you change the blend mode in the > monochrome iop? Is there a technique which requires a special blend mode > for it?
well, I was playing with a method that takes the luminosity channel, multiplies it by itself and through a blending operation with a mask equal to the inverse of the same input luminosity. In the web you will find that this method is called the Gorman-Holvert conversion. In other words, a monochrome conversion that takes just the luminosity channel, blends in multiply mode with a 'drawn' mask equal to the inverse of the input luminosity. For playing with such a method I locally modified dt's source code. In the process I realized that in dt any blending operation would always bring color back to the image, even when perhaps that was not the purpose of the associated module (monochrome in this case). dt modules do not announce such intents in any way (e.g. dt_iop_colorspace_type_t does not include a grayscale/monochrome option). Oh well, I'm not really convinced with the aesthetic results of the previously described method, but surfing dt's code was an interesting exercise. Rodrigo > > hal ------------------------------------------------------------------------------ October Webinars: Code for Performance Free Intel webinars can help you accelerate application performance. Explore tips for MPI, OpenMP, advanced profiling, and more. Get the most from the latest Intel processors and coprocessors. See abstracts and register > http://pubads.g.doubleclick.net/gampad/clk?id=60135031&iu=/4140/ostg.clktrk _______________________________________________ darktable-devel mailing list darktable-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/darktable-devel
