[argyllcms] Re: ColorMunki measurement drift

  • From: Graeme Gill <graeme@xxxxxxxxxxxxx>
  • To: argyllcms@xxxxxxxxxxxxx
  • Date: Thu, 07 Oct 2010 13:23:55 +1100

János, Tóth F. wrote:
Yes, the re-calibration bring the original X and Z coordinates closer to the
first results. The black drift was bigger than the drift in the chroma. But
the re-calibration didn't change the CCT, it monotonously increased during
the full measurement set. (And I think the display was relatively stable
after ~10 hours uptime.)

You have no way of knowing whether the display was stable or not.

I will be a full day job at the end: Two hours acclimatization, high setup
times (mentioned in the i1Pro thread) and the need for the adaptive mode
with higher integration times. And a lot of black/white drift compensation
measures, simply because it's a very long measure set anyway. :)

That's one of the reasons people spend (a lot) more money on
better instruments - it saves them time, and increases confidence.

There is a saying - "you can't turn a sows ear into a silk purse",
and the sort of instrument you are using simply isn't designed
to be perfectly stable with regard to temperature. I don't think
this is an impediment to their normal use though.

And it reminds me to another question:
You say that the default mode may gives us more coherent results because the
adaptive mode works with random integration times.
Can't we use constant (but user defined and high) integration times?

No, because then the instrument sensor will get saturated on brighter
patches (quite apart from enormously increasing the measurement time).

Graeme Gill.

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