[argyllcms] Re: Bad measurements & white point calibration with Argyll 0.7b7 and GretagMacbeth i1Display 2
- From: Graeme Gill <graeme@xxxxxxxxxxxxx>
- To: argyllcms@xxxxxxxxxxxxx
- Date: Thu, 10 Jan 2008 19:06:33 +1100
Craig Ringer wrote:
That's entirely true, there is indeed no proof the vendor tools managed
to match D65. However, in this case the on-screen appearance of mid
greys is a bright blue-purple when dispcal resports the white point to
be near D65. We're talking serious blue here, this is not a minor colour
cast. I know it's usually unwise to trust your own perception, but there
are some points beyond which it becomes hard to argue.
But adjusting the white point is not intended to adjust
mid greys to the same white point. They go along for
the ride, and end up wherever the monitor manufacturer
leaves them to end up. Only after running and applying calibration
can you then evaluate where the mid greys end up.
That doesn't mean that the white point being achieved isn't in fact D65
- the display could just be doing something completely insane with the
mid tones.
Sounds the most likely explanation to me, given that such
"R/G/B gain" controls are fake (they manipulate the
pixel levels).
> I'm more inclined to believe a meter reading or data
processing fault, though, given that I also get bad profiles on two
different machines from dispcal when using this colorimeter and I have
other indications that the vendor-software-produced profiles are at
least OK.
Have you gone through the process of calibration, and applied
the resulting curves ? How are the mid-greys after that ?
What does verification report ? What do the .cal files look like ?
Graeme Gill.
Other related posts:
