Hi, Am 09.11.2010 19:01, schrieb Graeme Gill:
Darzur wrote:It shows, that despite of agreement shown in above report (0.2% error fo 50% mark) LUTs were corrected by 5% down at 50% mark.But you don't indicate where this curve comes from. What are the axes ?
It's just a plot of the values in the .cal file (but scaled to 0...255 instead of the Argyll range of 0.0...1.0).
So image wasdarkened by 5% while it should reamain almost unchanged (due to 0.2% error). This report (with 0.2% error) was done on uncalibrated monitor just before calibration and curves shown above are a result of this calibration. It's strange for me that correction to LUT's is so big (5% darker at 50% mark) while it should be almost nonexistent (0.2%).Hmm. I'm not really sure if there is a problem, or if any problem is really fixable. Because the display has not been adjusted at that stage, it's possible that the targets are approximate, and that therefore the 50% target during calibration is slightly different to the one computed during the actual calibration. Since there is lot of interaction amongst the target values (ie. white level may change due to the white point to keep it in gamut, and then this will change the target curve, and even more complex interactions with regard to the black points influence on the target curve), I'm not sure that there is actually anything wrong with this. I would need to look into things in a lot more detail to determine how it actually works. If the result is too dark, reduce your target gamma.
I think the whole 'issue' is that a too low quality (dispcal -qv) was used in the creation of the .cal file.
Regards -- Florian Höch