[argyllcms] Re: 1st post (Spyder 3 Express + Dell 2711)
- From: Roger Breton <graxx@xxxxxxxxxxxx>
- To: argyllcms@xxxxxxxxxxxxx
- Date: Thu, 09 Dec 2010 07:22:26 -0500
Knut,
The videoLUT is an RGB table with 256 entries for each RGB color. All good
video cards have an 8bit LUT. It is 'linear' by default, meaning what
applications write in video is equal to the signal sent out to the monitor.
But it's possible to alter the content of the videoLUT, to calibrate the
display, so that, for instance, grays come out a certain color all the way
from black to white. Calibration is one of the 'service' offered by Argyll.
Profiling is what happens 'after' the videoLUT have been properly set,
according to a desired behaviour.
Roger
From: argyllcms-bounce@xxxxxxxxxxxxx [mailto:argyllcms-bounce@xxxxxxxxxxxxx]
On Behalf Of Knut Inge
Sent: December-09-10 6:15 AM
To: argyllcms@xxxxxxxxxxxxx
Subject: [argyllcms] Re: 1st post (Spyder 3 Express + Dell 2711)
On Thu, Dec 9, 2010 at 8:34 AM, Graeme Gill <graeme@xxxxxxxxxxxxx> wrote:
Knut Inge wrote:
Is the LUT included in the ICC profile? If not, how can I make any sensible
comparision between my ICC profile and downloaded ICC profiles if all of
them assume some non-included LUT that does per-channel gain?
Which LUT are you referring to ? The calibration VideoLUT or
matrix/shaper shaper LUTs, or the cLUT device LUTs or the
cLUT multi-dimensional LUT or the cLUT PCS LUTs ?
Graeme Gill.
I thought I was confused earlier...
I am referring to the info quoted below. I thought that the ICC/profiling
acted as an absolute and relevant characterization of the display in itself.
Judging from Sam Berrys response, it is not totally so, you first need to do
calibration. Since he can see from my ICC profile that I did not do
calibration, I am assuming that it is some "stuff" that will go into my
graphics card, altering the apparent display characteristics and included in
the loop while profiling the display. Is that the VideoLUT?
On Wed, Dec 8, 2010 at 10:19 PM, Sam Berry <samkberry@xxxxxxxxxxxxxx> wrote:
Your dispcalgui results, however, suggest that you have not calibrated the
display to D65 first though. The results are not directly comparable unless
they are all relative to the same white point.
New and updated table of profiles. Now I am doing profile+calibrate, and I
included dgm's measurement using the eye one display2
Spyder 3 express
SN: 030197xx
Instrument Version: sw 1.2/hw 4CL
Software version: 4.0.1
All profiles obtained with out-of-the-box display settings.
"Spyder software" is my measurement using the software that came with my
Spyder 3 express
"DispCalGui" is my measurement using the same calibrator but the GUI for
ArgyllCMS - NOW USING CALIBRATION + PROFILING
"TFTCentral" is the "Dell U2711 Standard Profile" from the review at
http://www.tftcentral.co.uk/icc_profiles/Dell%20U2711%20-%20Collection.zip
"Eye one D2" is an Eye One Display2 measurement kindly provided by DMG
"Nec271w driver" is from the Nec driver available at
http://www.necdisplay.com/cms/documents/Drivers/PA271W.zip
Using ICC Profile Inspector
Spyder software DispCalGui TFTcentral Eye one D2 Nec271w driver
Illuminant:
X 0.96420 0.96420 0.96420 0.96420 0.96420
Y 1.00000 1.00000 1.00000 1.00000 1.00000
Z 0.82491 0.82491 0.82491 0.82491 0.82489
luminance:
181
MediaWhitePoint Tag
X 0.94728 0.94891 0.96420 0.93262 0.95137
Y 1.00000 1.00000 1.00000 1.00000 1.00000
Z 1.09006 1.09258 0.82491 0.95439 1.08815
x 0.311878 0.311989 0.345702 0.323040 0.313000
y 0.329235 0.328786 0.358537 0.346379 0.328999
MediaBlackPoint Tag
X 0.00250 0.00154 0.00092
Y 0.00264 0.00148 0.00104
Z 0.00288 0.00194 0.00189
x 0.311721 0.310484 0.238961
y 0.329177 0.298387 0.270130
RedColorant Tag
X 0.65756 0.66727 0.53729 0.60466 0.60602
Y 0.30211 0.30634 0.21552 0.26689 0.27550
Z 0.00958 0.00929 0.00783 0.00929 0.00694
x 0.678421 0.678879 0.706366 0.686458 0.682102
y 0.311695 0.311670 0.283340 0.302995 0.310087
GreenColorant Tag
X 0.17140 0.16295 0.28874 0.22639 0.21756
Y 0.65845 0.65848 0.73769 0.68779 0.67461
Z 0.10768 0.11018 0.07498 0.06554 0.08890
x 0.182821 0.174912 0.262155 0.231076 0.221758
y 0.702324 0.706819 0.669769 0.702027 0.687627
BlueColorant Tag
X 0.13524 0.13397 0.13817 0.13315 0.14064
Y 0.03944 0.03519 0.04680 0.04532 0.04996
Z 0.70763 0.70543 0.74210 0.75006 0.72908
x 0.153279 0.153180 0.149039 0.143399 0.152923
y 0.044701 0.040236 0.050482 0.048808 0.054323
rTRC
gamma = 2.2 256 points gamma = 2.2 256 points gamma = 2.2
gTRC
gamma = 2.2 256 points gamma = 2.2 256 points gamma = 2.2
bTRC
gamma = 2.2 256 points gamma = 2.2 256 points gamma = 2.2
Now, "Spyder software" and "DispCalcGui" seems reasonably consistent,
eliminating one potential source of errors. So perhaps my probe is bad, or
perhaps my display really needs a lot more gain in the reds to do D65?
Thing is, when I look at my "calibration curves", red is 255->255 while blue
and green are 255->203. In other words, calibration chose to put massive
gain into the red channel. How do I compare the sanity of this to other
sources if the calibration curve is not included in the ICC?
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