A Theoretical and Experimental Comparison of GRACoL and ISO approaches to Press Characterization and the Data Set Produced.

by Greg Radencic, PIA/GATF

There is admiteddly great discussion for different color controls on press. This paper attempts an objective evaluation.

ISO 12647-2 defines colorimetric values for CMYK solids and densitometric control of tone reproduction. Grey balance is a secondary control in ISO.
G7 is a calibration method for proofing and printing and uses colorimetry through grey balance measurements.

When they run the G7: the calibration software doesn't perform a good calibration to grey below 30% and above 60% dot areas. G7 has admitted the problem and they said they will fix it. (I jut bought the s/w by the way... a bit disturbing to know that I bought sthg that might be wrong!?!)
When they run the ISO: it was succesful with nice grey.