Frédéric, Am 31.12.06, 11:36 +0100 schrieb Frédéric: > I have a strange behaviour with xcalib vs dispwin when loading LUT. They do > not seem to read the vcgtag the same way, depending of the profile. > > Let me try to explain... > > I attached a profile coming with xcalib package. This profile has a 2.2 > gamma. When loaded with xcalib, it does not change anything to my > uncalibrated screen (no previous profile loaded). But when loaded with > dispwin, the screen becomes very bright. xcalib should change the grafics card gamma table as described in the vcgt tag. I would guess xcalib is not supporting the parametric entry (~2.2) in opposite to the most often used curves. The ICC Examin grafic cards gamma window (ctrl-t) window should show you the current state of the gamma table in your grafic card. A vcgt entry of 2.2 is big and should affect the calibration and appearance of the monitor clearly. > *But*, when I load an Argyll generated profile (also attached), they both > give the same result! The argyll profile uses a curved vcgt tag. > I had a look in the profiles, with iccexamin, and I saw differences; it > seems that the vcgtag is linear in Argyll generated profile, even if it is > a 2.2 gamma profile. But I also see that the [rgb]TRC tags are, in both > cases, the same (2.2 gamma curved). The vcgt tag is independent of the TRC curves. Vcgt stores a calibration, inside the profile. In opposite the TRC curves describe the colour space after the calibration or the appliance of the vcgt curves to the grafic card LUTs. > Graeme, can you explain me how exaclty dispwin loads LUT? Do you know why > xcalib does not give the same results only on its sample file? regards Kai-Uwe Behrmann -- development for color management www.behrmann.name + www.oyranos.org + www.cinepaint.org