GRACoL as opposed to SWOP colour spaces

[Stephen Marsh]

SWOP, Gracol and Fogra should all be using ISO2846 compliant inksets, but perhaps with different acheivable solid CIELab values due to differences in substrate. Gracol and Fogra 39 are actually based off of the same characterization data, with tweaks to gracol for tonality and grey balance.

Thanks for the clarification, perhaps the media and solid ink density is what accounts for the differences in the L*a*b* values.


Stephen Marsh

[rich apollo]

Lukas, if it helps to think in Euro terms, one could say that SWOP is "similar" to F28 and GRACoL is "similar" to F39 (however SWOP is targeting a different inkset, so there is more of a discrepency than with the Fogra spaces which are more similar to each other).

Stephen,
Why do you say "…SWOP is targeting a different inkset…"?

[Stephen Marsh]

Stephen,
Why do you say "…SWOP is targeting a different inkset…"?

When I have compared the solid L*a*b* values of the three most common SWOP profiles to each other, GRACoL and Fogra spaces - the differences made me think that the issue was inksets rather than web vs. flatsheet and stock and solid ink density.

Stephen Marsh

[danremaley]

>since most peoples working space is SWOP.

How can what you said be true if most of his client files are SWOP? He's just introduced an unnecessary conversion and you can't get more color than they send you. I mewan the man said most people are using SWOP as is the Adobe default.

For more than 50 years color seps. were made to SWOP standards, (litho had no standards) so the publication industry attempted to get the web printers to proof and print to a standard. Photoshop's default is at, or near, this same 20% midtone gain. In my opinion the best numbers to print to are (DRY) 1.00Y 1.30C 1.40M 1.70 K. With midtone gains of 18%Y 20%M 20%C 22%K. Gracol calls for higher densities but that will cause a Mag. cast at these gain numbers. I teach the pressroom to print the Mag/cyan gains the same and Yelo 2% less - makes perfect gray balance. Lighter or darker depending on the numbers, but most important gray, with ISO inks.
Dan Remaley