[argyllcms] Re: 10-bit/color systems
- From: Kai-Uwe Behrmann <ku.b@xxxxxx>
- To: ArgyllCMS <argyllcms@xxxxxxxxxxxxx>
- Date: Thu, 2 Dec 2010 10:00:19 +0100 (MET)
Am 02.12.10, 01:06 -0500 schrieb FreeLists Mailing List Manager:
Date: Wed, 1 Dec 2010 19:44:15 +0100
Subject: [argyllcms] 10-bit/color systems
From: =?ISO-8859-1?B?SuFub3MsIFTzdGggRi4=?= <janos666@xxxxxxxxxx>
/// OFF
Now, I can confirm that the Dell U2410 (A00 hardware A02 firmware in my
case) could really work in 10 bit/color mode!
I feel it's important to say, because I couldn't find any reports about a
success. I found only questions with doubts and answers from expert
smart@sses that "Poor stupid man. Of course, it won't work! Do you think you
can have a 10-bit display under $2000? Stop asking stupid questions, will
you? Read some reviews instead!." - ~ Spyre's opinion in my words. :D)
/// OFF
Its just some different electronic. No manual soldering of transitors ;-)
But when I zoomed to the near-black scale, the superiority of the 10-bit
output wasn't so obvious.
- I could see some banding here, in 8-bit mode, but the white balance was
OK. The gradient had 'gray' tones. (As I expected it on a calibrated
display, where the calibration operates with 10-bit precision anyway).
- When PS was in 10-bit mode, the banding was much weaker BUT I could notice
some colorizations.
I didn't notice this colorization until I zoomed into the problematic
segment of the gradient but it looks like a heavy colorization.
So... What do you think about this colorization?
Strange. I do not see colorisations. After putting my monitor into 10-bit
p channel and full brightness my synthetic gray gradient looks smooth.
OpenGL applications like ICC Examin look smooth, other than in 8-bit mode.
I watched the gray gradient with a local test utility to map on
a OpenGL texture, as this is currently the easiest way to write 16-bit
values into the frame buffer.
The colour conversion is a texture lookup inside the compiz window manager
with the CompICC colour server plugin[1]. In this case it converts from
sRGB to a matrix shaper profile per monitor output. The texture has 64
GRIDPOINTS and was created with lcms or lcm2, depending what is actually
active in Oyranos.
I am used to see each step when moving a gradient like the tested one
around. It looks now as one would change the signal in a analog way with a
elektric resistor. Being familiar with all the 8-bit banding since years
it appears somewhat like magic.
Did it come from the limitations of the 10-bit output?
I would expect the ATI card to work correctly in the digital domain.
But your signal has to pass several software and hardware stages. Best
would be to exchange parts or better to measure at several point. But
thats much work.
kind regards
Kai-Uwe Behrmann
--
developing for colour management
www.behrmann.name + www.oyranos.org
[1] http://compicc.sourceforge.net
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