[argyllcms] Re: relativ volume of gamut -- vrml comparison?

  • From: Graeme Gill <graeme@xxxxxxxxxxxxx>
  • To: argyllcms@xxxxxxxxxxxxx
  • Date: Sun, 06 Jan 2008 12:25:15 +1100

Gerhard Fuernkranz wrote:
Before talking about your particular numbers, IMO the basic question is,
what's your understanding of a "camera's gamut"? How do you define the
gamut of an _input device_, like a camera or scanner?

In one sense a camera may have a gamut, and that is the range
of CIE values representable by the full range of combinations
of it's device values. In this sense, a camera gamut could
be computed in the same fashion as a display gamut, if the
camera response is modelled by shaper curves and a matrix.

There is no guarantee though, that this "gamut" can actually
be reached by any possible real world input spectrum.

A LUT based input profile can't be used in the same way though,
since it will be extrapolating (usually badly) outside the
range of CIE values using in the characterization chart.

Input devices can pretty easily be arranged to have
device value ranges that exceed the visible gamut,
making such an "input device gamut" not very useful for anything
(in the same way as an ICC PCS gamut is not very useful - it's
so big that there is little information represented by it.)

Graeme Gill.

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