[argyllcms] Re: spotread Question

  • From: "Brian W. Gortney, II" <bwg@xxxxxxxxxxxxxxxx>
  • To: argyllcms@xxxxxxxxxxxxx
  • Date: Wed, 9 Aug 2017 17:25:47 -0400

Thanks for the reply, Florian.

I know it's not a laboratory grade device, but outside of where this issue is present (i.e., in the area where the readings are relatively range-bound) it'll work for my purposes.  I do recognize the device is within spec, though the ~0.2% is more variation than I'd like to see; so, while I get that it's accurate enough for a 'prosumer' spectrophotometer (and appropriate for its intended application(s)), in this case 'pretty inconsistent' applies (for me).

I guess I'm mostly just wondering if others agree that this is likely an illuminant temperature-related issue, -or- if anyone has any other thoughts/insights into what's actually going on (either physically or in firmware or software, if anything), -and/or- if there are any other ways to eke out the performance I need, if anyone has any ideas.

Thanks again,


On 8/9/2017 14:24, Florian Höch wrote:


Am 09.08.2017 um 19:36 schrieb Brian W. Gortney, II:
A quick question for the list and/or Graeme:  I'm using spotread with an
i1Pro2 (rev E) to read XYZ values to be later processed, but I'm seeing
readings (in a fixed spot) that are initially pretty inconsistent.
I wouldn't call the variation seen "pretty inconsistent", but it depends
on your use case (an i1Pro2 isn't laboratory grade equipment). It looks
to be within specification: X-Rite quotes the i1Pro2's short-term
repeatability as 0.1 dE94 on subsequent white readings [1], and taking
the ones with the lowest and highest Y of your measurements (XYZ
76.14622 79.73407 66.99983 and 76.31308 79.90468 67.22933), I arrive at
a dE94 of 0.109 which seems fine (and this is the actual color
difference, not only Y). If we instead look at the more perceptual L*
difference, it's only 0.08%.



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