Hi Jo ! Thanks for your answer.
So this doesn't explain why the global colorpicker readings change depending on the display ICC profile, nor why using a log encoding between -2.5 and 2.5 EV, the grey gets remapped to L = 77 instead of 50. I believe there is a gamma correction where it doesn't belong. Where is the code for the colorpicker ? Regards, Aurélien. Le 02/11/2018 à 06:17, johannes hanika a écrit : > heya, > > it used to do the gamma in the olden days. now it just does what you > observed: convert to uint8 for display and any marshalling of data at > the end of the pipeline in gui mode can take place here. it's > certainly not applying gamma. i suppose we could delete these old > gamma lut table lines of code and just round directly in process(). > > cheers, > jo > On Thu, Nov 1, 2018 at 3:52 PM Aurélien Pierre > <rese...@aurelienpierre.com> wrote: >> Hi, >> >> there is in dt an hidden IOP named gamma.c that is the last one in the >> pixelpipe. Looking at the code, it is useful to display the masks and >> convert the pixels to uint8 values. >> >> However, it does a gamma conversion too, with a linear and gamma parameters. >> First of all, this conversion seems damaging in a calibrated and linear >> workflow because it (seems to) prevents the color picker to get accurate >> pixel values readings. >> >> Then, I don't see where the gamma and linear parameters are grabbed. Could >> anyone tell me what it does and how ? Having an arbitrary gamma conversion >> there could be redundant with the display gamma and is a serious matter for >> color management. >> >> Thanks, >> >> Aurélien. >> >> >> ___________________________________________________________________________ >> darktable developer mailing list to unsubscribe send a mail to >> darktable-dev+unsubscr...@lists.darktable.org > ___________________________________________________________________________ > darktable developer mailing list > to unsubscribe send a mail to darktable-dev+unsubscr...@lists.darktable.org > ___________________________________________________________________________ darktable developer mailing list to unsubscribe send a mail to darktable-dev+unsubscr...@lists.darktable.org
