Interpreting "validation record" and "target/result" post-calibration?

Discussion in 'Digital Darkroom' started by attila.ataner, Sep 25, 2008.

  1. Dear All, I use the Eizo ColorEdge CE240W as my main monitor. I calibrate it with the Spyder2 and Eizo's ColorNavigator software. After each calibration, ColorNavigator produces a "validation record", which consists of a long list of figures as shown in screen captures, as well as a short "target/result" list. (ColorNavigator also provides options for more detailed validation records, and produces several seemingly different sets of data - for example, CIE1976 or CIE2000, plus something called a "Delta-E" validation result graph.) I understand, generally, that this is supposed to show the variations between the target settings and the actual settings achieved after a calibration. Beyond that, I have no clue how to interpret the validation results/figures/data. I called Eizo technical support and, although they have been very helpful in all other respects, on this one they couldn't provide me with a simple explanation and ended up, basically, saying I need a degree in color management to understand it properly. (I have a couple of degrees in other areas, but, alas, I truly am too dumb for most tech/computer/engineering stuff - sorry!) I don't need a detailed explanation of what it all means - just a rule of thumb to have an idea if anything is seriously off with the calibration and/or the monitor. Put simply: how do I know if the variation between the calibration target and the actual achieved result is big enough to be of concern? Many thanks in advance for any guidance. Cheers!
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  2. If this article http://en.wikipedia.org/wiki/Delta_E is correct, and you are using the CIE76 formula (the heading in your example reads CIE 1976) than any delta-E under 2.3 is under the Just Noticeable Difference (JND) .
     
  3. I think a grounding in mathematical statistics or numerical analysis would be better than a degree in Color Management. I don't wonder why you couldn't get a straight answer from a computer tech. Look up something about curve fitting and error analysis (typically root sum square deviations). Or do as I do, just accept the results - if it works, don't fix it.
     
  4. For practical purposes delta E is the difference between what monitor displays and what the profile describes for a given color patch. Less than 3 is basicaly unnoticeable to a human eye (2.3 if you are a perfectionist, some people are happy with 4). In your case the threshhold is set to a bit over 3 and the values over that are highlighted in yellow. Essentially it means that your profile inaccurately describes the monitor output and you need to recalibrate.

    The numbers in the table just show the RGB values of a color patch, what was phisically measured by the colorimeter (in your chosen coordinates) and what was expected according to the existing profile.

    If you keep getting those delta E errors you need to reexamine your setup and workflow and figure out why you can not reach your calibration targets.
     
  5. As far as Eizo tech support I wouldn't expect much of them. I asked Eizo reps at a Javitz show which targets were available in ColorNavigator and their most technically informed guy answered that there are no targets to speak of in their software. They didn't have the software loaded, either.
     

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