[argyllcms] Re: The different color temperatures: questions: Please look again!

-------- Original-Nachricht --------
> Datum: Thu, 16 Apr 2009 08:41:59 -0500
> Von: Leonard Evens <len@xxxxxxxxxxxxxxxxxxxxx>
> An: argyllcms@xxxxxxxxxxxxx
> Betreff: [argyllcms] Re: The different color temperatures:...

> I still haven't found anything from Samsung about the `Color
> Modes': Custom, sRGB, AdobeRGB, Emulation, and Calibration,
> but experimentation shows, as you say, that only under Custom
> can you adjust Brightness, Constrast, or the Color controls.
> 
> By googling, I found a review which told me that in Emulation and
> Calibration mode that data is loaded directly into the monitor rather
> than in the video card.

Yes, the calibration is loaded into the monitor (and is persistently stored in 
the monitor until you re-calibrate it or reset it to factory defaults).

> I presume that something similar happens with
> sRGB and AdobeRGB.

Yes, this applies to all four modes (Calibration, sRGB, AdodeRGB and Emulation).

> I also presume that if I use Natural Color Expert to
> do what it calls `Calibrate' and which may be something
> intermediate between calibration and profiling, I should
> have the Mode set to Calibration.
> I don't understand just what Emulation is for, but I
> presume it is another way of loading some data determined
> A in another manner into the monitor.

In Calibration mode, the monitor uses its native (wide gamut) primaries, and 
the luminance, white point chromaticity and gamma targets are established by 
NCE (and eventually the resulting calibration is stored in the monitor).

In Emulation mode, the XL20 attempts to emulate the characteritics of a 
different monitor. When you set up the Emulation mode with NCE then you have to 
supply the ICC profile for the (other) monitor which should be emulated by the 
XL20, and a luminance target. I.e. the major difference between Calibration and 
Emulation mode is, that in Emulation mode the monitor won't use it's native 
primaries, but emulate different ones.

sRGB and AdobeRGB mode are just special cases of Emulation mode, where the XL20 
emulates the sRGB color space or the AdobeRGB color space.

> Finally, I presume all this works only under Windows
> (or MacOS), and not under Linux.

No, not under Linux...

You can of course calibrate the monitor once under Windows, and then use the 
calibrated monitor subsequently under Linux.

You possibly still need to fine-tune it under Linux with dispcal (using the 
graphics card LUTs), since the given gamma target and gray balance are not 
established by NCE too accurately (at last not on my XL20). The white point 
target on the other hand is established by NCE pretty accurately (thus dispcal 
w/o specifying any WP target should suffice).

> If indeed there is some way to load data under Linux
> directly into the monitor, I should know about it. Perhaps
> ddcontrol, mentioned by Kurt, can do that, but so far I
> haven't been able to get it to compile under Fedora 9
> because of problems with the version of pciutils provided
> by Fedora.

Don't waste your time, ddccontrol can't (at least not currently).

I've already spent some efforts to trace NCE's I²C communication with the 
monitor. I already managed to get a hex dump of the packets, but it seems not 
to be trivial to interpret the data (although there seem to be not so many 
different commands involved, when a calibration is carried out).

Regards,
Gerhard

-- 
Neu: GMX FreeDSL Komplettanschluss mit DSL 6.000 Flatrate + Telefonanschluss 
für nur 17,95 Euro/mtl.!* 
http://dslspecial.gmx.de/freedsl-surfflat/?ac=OM.AD.PD003K11308T4569a

Other related posts: