[argyllcms] Re: Displays with internal gamut emulation

  • From: János, Tóth F. <janos666@xxxxxxxxxx>
  • To: argyllcms@xxxxxxxxxxxxx
  • Date: Sat, 21 Aug 2010 20:31:31 +0200

I think I already gave you every instructions in my older emails. A little
summary:

- This is a real Wide Gamut display. You need a spectrophotometer (like
ColorMunki, EyeOne Pro) or may be a colorimeter (like the EyeOne Display 2,
Spyder x or DTPxx) with a unique correction matrix (specifically created for
your given instrument and display combination - averaged "generic"
corrections are be better than nothong but far from good) and a software
which supports these correction matrices (like iColor Display 3.7 - and
nothing else, I think - CalMan and HCFR won't create calibration LUTs and
ICC files.).

- I think that ArgyllCMS is the best display calibration software, so I
recommend it. The only warning that you should wait a little bit for the new
bugfix version. (But the current version is not totally useless either.)

- You should choose one of these display presets: sRGB, AdobeRGB, Standard

*  You should chose the sRGB preset for any kind of "general PC usage"
** You should choose the AdobeRGB preset if you are absolutely sure that you
need the AdobeRGB gamut (for some specific jobs) but you are unsure about
the quality of your software color management system. (8 bit framebuffers vs
12 bit hardware 3DLUTs, given software quality, etc.)
*** If you are absolutely sure that you will work with a software which
offers high quality color correction and/so you can benefit from the wider
gamut and slightly higher starting contrast ratio and color accuracy, you
can choose the Standard mode. (Advanced softwares with high quality color
management and professional VGA cards with 10 bit/color framebuffering, or 8
bit framebuffers but softwares with high quality dithering, or special needs
for wider gamuts, etc.)

- As a last suggestion. You should take a backup photo of your factory OSD
and fine tune your RGB Gain settings.
* Set every Gains to 255 first.
** The highest Gain should always remain 255
*** You may want to set these Gains for the 6500K preset because Standar
mode has smooth RGB level graphs.
**** But you should keep the other settings at 255-255-255 because the
emulated modes (sRGB, AdobeRGB) have crossing RGB level graphs, so you can't
really optimize your white balance with these Gains. (But the lowering of
these Gains will permanently reduce the contrast ratio and the available
color shades. So leave it to ArgyllCMS to decide about the best solution
with higher accuracy ¤¤¤)

¤¤¤ I assumed that you have a VGA card with DeepColor support, do you?
(HD4+, GTX2xx+, or the equivalent professional SKUs, as I know). But this
won't be worse with 8 bit/color connection either (as the levels will always
cross each others, and those Gains works with 8 bit values as well...)

××× But you should check it for yourself. Do a calibration with maximized
RGB Gains to see of the LUT curves are crossing each others of not. If they
are smooth and theres is no crossing, you should optimize your white balance
with the RGB Gains forst. If they cross, you should keep the Gains
maximized...


I don't have any more ideas yet.

Or may be one: We have the compiled binaries of the A01 firmware image. Is
it possible to revers it with a GPGPU software and crack the internal LUTs?
:)

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