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Thread: G7 Calibration readings

  1. #1
    Join Date
    Sep 2016
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    Kansas City, MO
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    Default G7 Calibration readings

    When the collective 'we' perform the G7 calibration (I do the P2P51 Randomized 2-up) we get a pop-up window showing us the readings. We then accept or iterate. Where do these readings go to once we make our choice? I have looked everywhere I can think of to find them. Currently I take a screen grab and store each in a folder assigned to each machine by date.
    If these readings are stored someplace that I can get to on my windows 7 system, and if I am able to open and read them that would be great.
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  2. #2
    Join Date
    Apr 2010
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    Foster City, CA
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    Default

    Hi Bob.

    These screens just show the results of "testing" your Fiery calibration to see if it achieves G7 calibration even before you make a profile.

    When all the results are green, G7 passes. Sometimes this takes more than one try which is why we have the iterate button. The first G7 pass almost always fails, since we need the first set of P2P measurements to calculate the G7 calibration NPDC curves. We put these curves into the Fiery calibration and when you print the second P2P it should pass. Sometimes this takes a couple of iterations, which can happen if printer is varying page to page (hint - always print 10 copies and measure the last one) or if you are not measuring well with an ES-2000 (hint - make sure the ES-2000 aperture is always "flat" on the measuring board when you measuere, if it angles even a little bit the precision is reduced).

    Be aware that some users skip the G7 calibration since they know that once they make a good output profile and print with CMYK source set to a G7-based profile (any GRACol, SWOP, or any of the 2013 CRPC profiles), their prints will match G7 grayscale anyway and in many cases G7 targeted or colorspace if the gamut of the press/paper permit.

    ~Lou

  3. #3
    Join Date
    Sep 2016
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    Please help me out here,
    DO I iterate until I get all green, or do I iterate until I get another red and then back up to accept? I was under the impression that when I first get all green, while technically acceptable, to keep going on would bring my measurements closer and closer to the ideal parameters and possibly beyond until I reach another red reading.
    My hope of knowing if these readings are in fact temporarily stored someplace I could see when I past the ideal reading.
    All this said, I'm not really looking to make this more work for myself, I just have a level of ignorance regarding what is actually happening and a degree of OCD enough to try and achieve 'more perfect'.

  4. #4
    Join Date
    Apr 2010
    Location
    Foster City, CA
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    281

    Default RE: G7 Calibration readings

    Iterate until you get all green.

    When you make a device link profile from CPS Device Linker (or any other iterative optimization device link tool) you sometimes "overdo" the optimization so the delta E's go up and then we revert to the previous iteration with the lowest delta e values. You don't know when to stop since te DE's keep going down and lower is better.

    G7 is different - when you comply, everything is green, and you won't get any more compliant by iterating.

  5. #5
    Join Date
    Sep 2016
    Location
    Kansas City, MO
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    Default

    Awesome, thank you for the clarification. Now I can focus on doing my other responsibilities instead of over-thinking this one.

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