Paul,
Am 11.09.2017 um 17:47 schrieb Paul Sherfield <paul@missinghorsecons.co.uk>:
Hi
Been following this thread with interest.
So a few observations:
1) On making a profile from the Fogra 52 dataset, using ColorLogics ColorAnt and CoPra4 software, reducing the TAC to 260% and applling heavy GCR I get what seems to be a usable profile when tested using the stadard test images, Grainer Rainbow, etc.
2) However it is noticable when separating RGB B/W images that the CMY separations are not neutral, there are blue /black as reported by Martin.
which rendering intent? If rel.col. -> no surprise If perceptual, which mapping strategy did you choose in CoPrA?
If these are printed correctly would this be an issue? Hope not! The yellow separation, as reported by Martin is a little odd.
3) Soft proofing on screen seems to be a issue with M1 based profile with higher OBA¹s. I guess as the screen cannot show the OBA as the human eye would see then
The human eye doesn’t care how the perceived CIEXYZ is created. CIEXYZ=CIEXYZ means visual match (assuming you are a CIE standard observer). No OBA voodoo here :-)
, is shows the paper white, say -b10, as very blue.
Are you comparing the softproof to an actual FOGRA52 print in an ISO3664:2009 compliant viewing booth? From what I see in the field and is recommended in the Fogra Softproof Handbook, people choose the monitor’s luminance based on their viewing booth (typically 500lx converts to 160cd/sqm). One issue with softproofing in Photoshop then is that by applying abs.col. you loose so much luminance that you’ll never have an acceptable match. This also happens with softproofs for Newspaper which is not affected by OBA heavily.
Not sure this can be easier corrected?
Untested pragmatic idea (or call it educated guess): For every proofing condition you need to do a softproof for, place the pertinent paper into your viewing cabinet and select the monitor whitepoint adjustment aims in terms of cd/sqm and whitepoint xy in a way that monitor and paper visually match. Do this for every (or the problematic) paper. Switch the calibrations before doing the softproof in photoshop and use rel.col (so only switch on: Simulate black ink or whatever it is called in the english version). Of course this is not convenient with a 200€ monitor, but as far as I know all the monitors with built in hardware LUTs allow to switch calibration and monitor profile quickly. Regards Claas
4) Is Is there spectral data for Fogra52 as there is for 51?
Regards
Paul Sherfield
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Member - UK TC130 Technical Advisory Group (ISO 12647 Printing Standards) UK Expert: ISO TC130/Working Group 13 on certification of printing standards Chair BPIF Colour Quality Scheme Certification Steering Group
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