[argyllcms] Re: Correction for wide gamut screens and/or RGB-LED?

  • From: Graeme Gill <graeme@xxxxxxxxxxxxx>
  • To: argyllcms@xxxxxxxxxxxxx
  • Date: Tue, 06 Apr 2010 09:14:43 +1000

Steffen wrote:
How does ArgyllCMS cope with this, are there any plans (or even just
data on the deviation) for the future? I find that not only software

Currently the instruments are assumed to provide correct XYZ values.
Generally you get what you pay for in this regard. Some colorimeters
don't work so well on some displays, and this is a good reason for
buying a spectrometer.

While it's perfectly possible to create correction matrices for particular
display/colorimeter combinations, in practice there are stumbling blocks.

A major one is that it's a combinatorial explosion. I don't even have
access to all the displays that support in-display Luts, never mind the 
of other LCD displays out there, so I can't supply such correction
matrices. (I suspect it would be a full time job keeping up with them,
even if one were suppled monitors by all the manufacturers). The other
problem is that one particular instance of a colorimeter doesn't necessarily
represent the average for that type of instrument. One needs access to a
statistically significant number of instruments to overcome this problem.

[A systematized solution would involve the display manufacturers publishing
 the spectral characteristics of their displays in a standard format, and
 having some means of measuring the spectral sensitivities of the instruments.]

developers have to face the problem of designing their software so that
it uses some form of CMM, but that the profiling process itself is
affected by the changes in display technology.

The profiling is not affected. Shortcuts taken by the colorimeter makers
do affect their accuracy though.

Graeme Gill.

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