[argyllcms] Re: A question about Spyder 3 + samsung 940Z5L laptop again
- From: Florian Höch <lists+argyllcms@xxxxxxxxx>
- To: argyllcms@xxxxxxxxxxxxx
- Date: Sat, 27 Apr 2019 00:53:13 +0200
Hi,
Am 25.04.2019 um 23:03 schrieb Виталий Филиппов (Redacted sender vitalif
for DMARC):
Does dispcal create a "full conversion" ICC profile? As I understand yes,
because it's able to visualize the gamut.
While the Argyll `dispcal` command line tool can create a (simple)
shaper+matrix profile from the calibration measurements (-o option),
such a simple profile may not be sufficient if the display is relatively
non-linear (as is the case with many cheaper/TN panel, especially laptop
displays).
You may want to use dispread after calibration (making sure to apply the
calibration using the -k option) to measure a few hundred patches, and
then use colprof to create a cLUT-based profile from these measurements.
[ or use DisplayCAL with defaults and let it do all that for you. ]
But when I take an image and apply the sRGB->940z5l.icc transformation I
don't see the image change drastically. Colors remain mostly the same...
That's no surprise, the gamut described by your attached profile is very
similar to sRGB (except it falls short in the blue region, so doesn't
cover sRGB fully).
At the same time, it seems possible to pick similar colors by hand, for
example, for my eye #00AAFF on a "normal" screen looks very similar to
#3D97FF on 940Z5L. So it's capable of showing the color, but it probably
requires a matrix transformation to do so. As I understand that's what ICC
profile does - it specifies a matrix transformation in addition to LUTs.
Have you read the section in the Argyll docs about calibration vs
characterization?
Note that only the simplest form of profile uses a matrix (+ shaper
curves) to describe a display's response. This may work well for very
linear displays, but may not be very accurate for nonlinear ones (see my
comment above about cLUT profiles).
But why does my ICC profile fail then?...
Explain what you mean by 'fail'. An ICC profile does not make any
qualifying statements. It just characterizes the display.
Cheers,
Florian.
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