Re Gamma, dithering and device calibration
Re Gamma, dithering and device calibration
- Subject: Re Gamma, dithering and device calibration
- From: "Bruce J. Lindbloom" <email@hidden>
- Date: Sat, 03 Aug 2002 12:25:17 -0500
Mark Ward wrote:
>
Should pixels of (r,g,b)=(128,128,128) now be half as bright as those of
>
(255,255,255)? Ie if I make a checkerboard pattern of alternate (0,0,0) and
>
(255,255,255) pixels and do the squinty-eyes-thing, should it look the same
>
as a patch of (128,128,128)?
First of all, a checkerboard pattern is not a good choice for the
"squinty-eyes-thing" because on a monitor, the electron beam sweeps
horizontally so fast, that it cannot turn fully on and fully off on a
pixel-by-pixel basis. A better choice might be a repeating pattern of
horizontal lines, alternating in color between white and black.
If your display is truly set to gamma 2.2, then the brightness of the
"squinty" dithered pattern should look the same as a solid patch of pixel
value 186. (In gamma 2.2, a pixel value of 186 has half as much *energy* as
a pixel value of 255.)
--
Bruce J. Lindbloom
email@hidden
http://www.brucelindbloom.com
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