[argyllcms] Re: Wrong gamma reading with Spyder 3.

  • From: Graeme Gill <graeme@xxxxxxxxxxxxx>
  • To: argyllcms@xxxxxxxxxxxxx
  • Date: Mon, 08 Nov 2010 07:41:00 +1100

Darzur wrote:
black/white patterns and it's perfectly accurate. dispcal -r (or -R)
still reads D2.06 while in fact it's very close to G2.2 (visually
mathing 50% pattern to 186 RGB grey).

As explained in the link I posted before, Argyll reports an approximate
gamma that is the equivalent zero based (ie. no offset) power curve that
has the same value at 50% as the real curve. A visual scale based on
black and white stripes will (probably) be a power curve offset
at zero, because it is composed of a real black that is non-zero.

Naturally, these two different ways of interpreting gamma are
not the same.

Graeme Gill.

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