Re: "native" gamma (was: fundamental question - monitor profile as working RGB?)
Re: "native" gamma (was: fundamental question - monitor profile as working RGB?)
- Subject: Re: "native" gamma (was: fundamental question - monitor profile as working RGB?)
- From: bruce fraser <email@hidden>
- Date: Wed, 10 Dec 2003 08:19:54 -0800
At 8:22 AM -0600 12/10/03, email@hidden wrote:
The thread of this topic has lead me to another question...related to the
Barco Calibrator monitors. Is "Uncorrected Gamma" the same as native?
There are two choices in the Barco utility..."uncorrected" and "linear". I
am assuming (perhaps erroneously) that a linear gamma would be a gamma of
1.0 and that "native" and "uncorrected" are the same thing.
Can't help on that one-it's been a long time since I used a Barco-but
it would seem reasonable to believe that "uncorrected" meant just
that.
I'd like to hear more about why a native gamma would be theoretically
"better" then a gamma of 2.2 (or whatever your preference is). As a
devil's advocate kind of question, why not use the native whitepoint as
well?
Tweaking the gamma is always done in the video card's LUT, and since
video card vendors generally care more about how many shaded polygons
they can draw per nanosecond than they do about good color, those
LUTs are 8 bit. So tweaking the gamma is exactly like drawing an
8-bit gradient in Photoshop, then editing it with Levels. You may
start with 256 shades, but you'll end up with less. The bigger the
adjustment (i.e., the further you go from the monitor's native
behavior), the fewer levels you wind up with, and the more likely
you'll encounter visible posterization in gradients.
On a CRT you can adjust the white point by making analog adjustments
to the RGB gains, so there's no loss in digital counts, though you'll
lose luminance at lower color temperatures. On LCDs, I (and many
other) advocate using the native white point as well as the native
gamma. (Basically all there is to adjust on most current LCDs is the
strength of the backlight, though there are exceptions.)
Bruce
--
email@hidden
_______________________________________________
colorsync-users mailing list | email@hidden
Help/Unsubscribe/Archives:
http://www.lists.apple.com/mailman/listinfo/colorsync-users
Do not post admin requests to the list. They will be ignored.