ISO Coated v2 39L vs Gracol 7

[indy jones]

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.

[meddington]

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.

[David Milisock]

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.

[indy jones]

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.

[meddington]

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):


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dE Report

Number of Samples: 1617

Delta-E Formula dE76

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

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

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

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[indy jones]

Thanks Meddington for the info. We do not have Color Think Pro to make the comparison

[rich apollo]

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.

[meddington]

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