gamma correction

[Allen Akin]

On Fri, Dec 12, 2003 at 02:38:25PM +0100, Martijn Sipkema wrote:
| - (almost) no hardware can do per window gamma correction, i.e.
| gamma corrected and uncorrected visuals.

That's a workstation-world feature that hasn't gained any traction in
the PC world.  But I don't think it's a great loss, because now it's
common for windows to contain imagery from multiple sources with
different gammas, so a single per-window gamma doesn't help as much as
it used to.

| - most systems don't do full gamma correction in the framebuffer
| LUT. SGI has a default system gamma of 1.5, Mac uses 1.8. I
| suppose Windows uses 2.2.

It's actually a bit more complicated.  For various reasons I'd give
Charles Poynton's book "Digital Video and HDTV Algorithms and
Interfaces" only a qualified recommendation, but it does do a great job
explaining (with text and diagrams) exactly what's going on with gamma
in video, Windows, SGI, and Mac systems.  If you can buy or borrow a
copy, it's worth checking out.

Allen