Re: sRGB vs. sRGB IEC61966-2.1
Re: sRGB vs. sRGB IEC61966-2.1
- Subject: Re: sRGB vs. sRGB IEC61966-2.1
- From: John Gnaegy <email@hidden>
- Date: Thu, 12 Sep 2002 14:02:37 -0700
different. As it was explained to me by John Gnaegy - the Apple
version uses
the Bradford transform and the industry standard version the XYZ
transform.
I'm also advised that Kodak have another variation.
The alternative to Bradford is the Von Kries transformation. All the
profiles Apple now ships use the Bradford transform. XYZ is a kind of
intermediate space called a PCS (profile connection space), and its
alternative is Lab. Bradford vs. Von Kries, XYZ vs. Lab.
The only difference between sRGB IEC61966-2.1 and the sRGB Profile
Apple ships is at the low end of the gamma curve. The standard
specifies a linear response at the very darkest end of the range, then
a 2.2 gamma curve for everything else. Apple's sRGB Profile is a 2.2
gamma curve for its entirety, which can be described by a smaller
profile.
---
John Gnaegy
colorsync
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