[argyllcms] Re: Greenish cast in darker blacks

  • From: Graeme Gill <graeme@xxxxxxxxxxxxx>
  • To: argyllcms@xxxxxxxxxxxxx
  • Date: Wed, 23 Dec 2009 14:30:18 +1100

Pascal de Bruijn wrote:
color cast. Since Firefox 3.5 doesn't use LCMS anymore, I'm guessing
this isn't a CMM issue.

Possibly. Other explanations might be:

  The white point is too different from the black point, and you
  are noticing the transition from the neutral target to the black
  point (ie. with the LCD default -k 0). Shifting the white target
  to a hue nearer that of black may help, or using a -k > 0
  may help at some cost to the contrast range.

  It might be an optical effect (although your screen captures
  hint otherwise). I've noticed some displays have quite
  a hue shift with viewing angle near black, particularly
  if the color is not naturally neutral. A larger -A parameter
  may help in this situation (assuming -k 0).

  It may be that the target curve shape is too much of a stretch
  for the display near the dark end. This may be because the
  current default is to use an input offset model of gamma curve
  shape. You could try all output offset as an alternative (-f 1).
  [I'm thinking of making this the default in 1.1.0 RC3].

Graeme Gill.

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