[argyllcms] Re: Plasma TV (Pana G20) + ColorMunki + HD5450 + ArgyllCMS -> HELP!
- From: Graeme Gill <graeme@xxxxxxxxxxxxx>
- To: argyllcms@xxxxxxxxxxxxx
- Date: Tue, 15 Mar 2011 15:42:57 +1100
János, Tóth F. wrote:
- Is the ColorMunki (in Adaptive HiRes mode) + ArgyllCMS (1.3.2) capable
to calibrate (and/or profile) displays with NeoPDP panels?
Given that the ColorMunki is a spectrometer, the likely answer is yes.
What reason would there be for it not to work ?
My biggest concern was that this TV doesn't show the usual 8-bit
gradient image. I saw a "noisy s##t" from a closer distance and a smooth
gradient from a bigger (normal viewing) distance (with less noise). But
I was unable to distinguish the gray shades from this distance. It felt
like some built-in de-banding (or blur, or something or other, but
nothing good...).
The basic problem with Plasma is that it has limited linear level control. The
initial panels had only 16 linear levels. Used without dithering this would
give horrible contouring/posterization, so they pulled every trick in the book
to
cover it up - spatial and dynamic dithering, hence the noise you notice.
The dynamic dithering also creates artefacts such as dynamic contouring,
where a moving image cancels the dynamic dithering.
Modern panels have increased the number of levels, but the basic problems
seem to remain, as you have noticed.
another problem here... I don't know. But it's not fair to say that this
panel has "6145 own gray shades". It couldn't reproduce a proper 8-bit
gradient, even with it's most friendly OSD settings. (Not to talk about
the other color modes...)
It would seem that marketing has lost touch with reality, if this is the
case.
I measured lower contrast ratio (with higher black level) than I usually
measure on my LCD (with it's initial settings before the WP adjustment).
It was ~800:1 but the perceived contrast ratio was very good. The black
looked much more deeper than the other LCD showed on the same room
(which measured around 950:1 before the calibration and 700:1 after).
This could be an angle of view thing. The instrument is measuring at
90 degrees, while LCD's tend to have a worse looking black at other
viewing angles. A phosphor based screen like a plasma will tend to look
more uniform from other viewing angles.
And a very strange thing: The report said that the VGA LUT precision is
10 bit/color.
How the hell??? The noise pattern on the display is so dummy that the
sensor can see only one smaller square of the bigger noise pattern. No
way that it can see the effect of the bigger noise pattern.
This was the point when I started to worry about the dithering of the
VGA card.
The instrument integration time is reasonably long so as to improve sensor
precision, and also average out any refresh frequencies. It could be that there
really is 10 bit over a long enough period. It's hard to know what to make
of your experience, since the characteristics of the display would have to
be examined in some detail to ascertain why it doesn't calibrate well.
Graeme Gill.
Other related posts:
