Hi,

>Personally, I do not think it's necessarily a good idea to try and avoid
>this.

>The gamma table is only for display *calibration*, and surely it is better
>to have a display which is more accurately calibrated? For example, if we 
>calibrate to a known standard such as sRGB, *non* colour managed 
>applications will display colour more accurately, because most images 
>today are assumed to be in the sRGB space. So, if the gamma tables are 
>loaded into the display, creating a very accurate gamma of 2.2 for all three 
>channels, that surely has no drawbacks whatsoever. Yes? Similarly, if the 
>gamma tables are used to *calibrate* the whitepoint (for example, if the 
>monitor doesn't have any controls to set the whitepoint), that again is an 
>advantage, with no downside at all.

This has been and still is a topic under hard discussion in many forums :-)

Of course this approach has advantages, but to my understanding also
has serious problems. Let's resume first how these profiles works.

A typical profile using vcgt is a "two step" beast. Fist step is applied on
computer startup. The profile loads the videocard with a compensation to 
make the display behave as a perfect 2.2 (or anything else) gamma.
Ok so far. But this does not change phosphor primaries, nor whitepoint.
So, all non-color managed applications are still operating in the native 
monitor space, only the gamma they "see" now is 2.2

Then comes the second part. To do compensation for white point and 
primaries, a color savvy app still needs to use the profile. Just the profile 
is assuming gamma of monitor as a perfect 2.2. At that point the effort 
required by the color managed app is exactly same as the profile were not
touched the hardware ramps at all.

Benefits? well, all non-color savvy apps does "see" a gamma of 2.2 But the 
primaries and white point are still wrong. Drawbacks? Setting the gamma
of videocard is hardly OS-dependent, so, lcms would not be portable if 
doing so. And more importantly, The profile is doing adjusts on your 
hardware, which many people probably don't want. I assume a profile is
a characterization of how a given display does behave, not a way to 
configure the display.

Anyway, just my 2 cents.

Regards,
Marti.






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