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  1. #1
    indy jones is offline Member
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    Default ISO Coated v2 39L vs Gracol 7

    Does any one have ISO Coated v2 data set, so I can compare to Gracol 7 data set on Measure Tool? I did download ISO data set but it is in different format when a do a comparison to Gracol 7 data set.

  2. #2
    meddington's Avatar
    meddington is offline Senior Member
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    Fogra 39L (data set for the ISO profile) is taken from an ECI target vs Gracol data based on IT8/7.4 target (1485 patches vs 1615 patches), so hard to compare apples to apples.

    A good way to do this is with ColorThink Pro, assigning the corresponding ISO-ECI and Gracol ICC profiles with absolute rendering to identical CMYK reference files, then comparing for delta E.

  3. #3
    David Milisock's Avatar
    David Milisock is offline Senior Member
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    Quote Originally Posted by indy jones View Post
    Does any one have ISO Coated v2 data set, so I can compare to Gracol 7 data set on Measure Tool? I did download ISO data set but it is in different format when a do a comparison to Gracol 7 data set.
    Ok I have a stupid question, why?

    I understand the technical concepts but in reality isn't it on the destination media where the differences are clear.

  4. #4
    indy jones is offline Member
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    We print Epson Proofs using BlackMagic rip that are Gracol 7 complaint. We have a Client that is ISO Coated v2 Certifed using GMG rip. We have a file we both ran threw our workflows. The proofs look slightly different. Looking at the ISO and Gracol 7 data sets, I did notice that trap green and blue have different LAB values. I want to compare the 2 data sets in detail to see where else is it different.

  5. #5
    meddington's Avatar
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    Using the method I mentioned previously, here's my result comparing the two (using Adobe generated Fogra39 & Gracol2006 ICC profiles and IT8/7.4 reference file):


    --------------------------------------------------

    dE Report

    Number of Samples: 1617

    Delta-E Formula dE76

    Overall - (1617 colors)
    --------------------------------------------------
    Average dE: 1.98
    Max dE: 5.30
    Min dE: 0.04
    StdDev dE: 0.88

    Best 90% - (1454 colors)
    --------------------------------------------------
    Average dE: 1.79
    Max dE: 3.12
    Min dE: 0.04
    StdDev dE: 0.68

    Worst 10% - (163 colors)
    --------------------------------------------------
    Average dE: 3.70
    Max dE: 5.30
    Min dE: 3.13
    StdDev dE: 0.57

    --------------------------------------------------
    --------------------------------------------------

  6. #6
    indy jones is offline Member
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    Thanks Meddington for the info. We do not have Color Think Pro to make the comparison

  7. #7
    rich apollo's Avatar
    rich apollo is offline Senior Member
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    Quote Originally Posted by indy jones View Post
    Thanks Meddington for the info. We do not have Color Think Pro to make the comparison
    Yeah, they're pretty darned close. Another exercise would involve a color target; any target, ECI2002, IT8-7/3 or /4, whatever. Open the target up, duplicate it. Apply one profile to one image, the other profile to the other image. Convert each to Lab using a colorimetric rendering intent. Then copy one onto a layer on top of the other. Set the layer mode to difference.

    Not to quibble with Mr. Eddington, but FOGRA 39L is an IT8-7/4. The dataset came out of PrintOpen which arranges the patches oddly.

    Attached is the data set sorted into the order of an IT8-7/4 (random layout), which takes waaaay more time to do than you'd expect. Michael's method is quicker.
    Attached Files Attached Files

  8. #8
    meddington's Avatar
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    Quote Originally Posted by rich apollo View Post
    Not to quibble with Mr. Eddington, but FOGRA 39L is an IT8-7/4. The dataset came out of PrintOpen which arranges the patches oddly.
    Oops, missed the "L". Thanks Rich


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