[argyllcms] Argyll 1.1.0 RC2 luminance readings high by ~4-6% with Eye-One Pro

  • From: Alexander <adfirestone@xxxxxxxxx>
  • To: argyllcms <argyllcms@xxxxxxxxxxxxx>
  • Date: Sun, 20 Dec 2009 14:14:14 -0800

I'm having an issue where the luminance readings from Argyll 1.1.0 RC2
are always high by about 4-6% when compared to any other application
that uses the EyeOne.dll SDK provided by X-Rite.

For example, if I calibrate to 95 cdm2 with Argyll, everything else
reports something around 90 cdm2. While this is quite an improvement
from Argyll 1.0.4 which always had high readings by something like
45%, it is still a bit off for me on my CRT with 1.1.0 RC2.

Anybody else with an Eye-One Pro seeing similar results with Argyll 1.1.0 RC2?

Graeme Gill, on a somewhat unrelated note could you add an option to
dispcal and dispread to always average by a user specified (or
automatic?) number of readings before recording/using/displaying any
such value? Adding a threshold value to the previous idea may not be a
bad idea either.

For example when the user turns this option on, Argyll would always
take a minimum of 2 readings for everything. If the two readings are
within 0.1 dE of each other, then they are averaged and the value is
used/displayed. If the two readings deviate more then 0.1 dE, then an
additional X (user specified, default 2) readings are taken and all
are averaged before the value is used/displayed. If a single readings
of the multiple readings deviates significantly more then the
former/following readings do from each other, then that oddball
reading is discarded before averaging takes place (if you had readings
of 0.3124, 0.3130, 0.3110, and 0.3220 then the last reading of 0.3220
would be discard as an oddball).

For all I know Argyll already does something like this automatically,
but if not I think it would be a handy feature for higher accuracy.

Since the values read jump around slightly on my CRT, especially for
dark readings (probably because of the Eye-One Pro which I've heard is
weak at low luminance), a functionality like I would think should lead
to higher quality readings/calibrations/profiles (while significantly
slower). On that note, an option to restrict this feature to low
luminance readings only for Eye-One Pro users so you don't take as
much of a speed hit from enabling the feature, would also be nice.

Good idea? Bad idea? Thoughts? Feasibility to implement?

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