Hello Petr, Your observations are right, there are large differences in dE between the ISOcoated profile and the ISO12647-2 standard. The values of the overprints in the standard are not normative and there is no dE specified as for the primaries. The values of the overprints are in discussion in the ISO TC130 committee and may be are changed in the near future to values better fitting actual printings. The ISOcoated is not a generic profile, it is derived from real printings without any modifications with respect to lab values. Currently it is not allowed to use other dE formulas. ISO12647-1 specifies dE76 as the only valid color difference formula in the graphic arts. This may change in future, but then the tolerances will also be changed. Kind regards, Guenter Bestmann Heidelberger Druckmaschinen AG Research & Development -----Original Message----- From: eci-en-admin(a)lists.transmedia.de [mailto:eci-en-admin@lists.transmedia.de] On Behalf Of Petr Lozan Sent: Monday, July 11, 2005 3:38 PM To: eci-en(a)lists.transmedia.de Subject: [ECI-EN] ISOCoated.icc versus ISO 12647-2:2004 Paper Type 1 (WB) Overprint Values Hello all, I compared colours of the overprints specified by ISO 12647-2:2004 (WB) and the Lab values I read on 100/100 samples which I had transferred from CMYK to Lab using abs col method and ACE in Photoshop CS and ISOCoated.icc profile. There were quite high DEs. C+M DE=10, M+Y DE=7.3, C+Y DE=5.2 May be this method of acquiring Lab values isn't too correct. Regardless the results surprised me, and I don't think it's only due to the way I got the numbers. An old Matchprint laminate proof I examined (using same method, I have its ICC profile) conforms to the values specified in the standard better than ISOCoated.icc profile :-( When I compare the samples using DEcmc, the results are more acceptable. But there are questions: is it OK if colour differences (DE, not cmc) are so high in this profile? Why this? Why data which, I think, couldn't too conform to the standard were used? Will be there more accurate generic profile with such a support as ISOCoated.icc has got? I'm novice in this field. (In writing in English too, I am sorry.) Please excuse me whether what I wrote is nonsense. But I want to know, where the truth is. I though the today best practise is using ISOCoated.icc. However, if the colour differences are so high, it would be better to use another profile. Wouldn't be? Regards, Petr Petr Lozan, Student - Higher Graphic School Prague, Czech Republic petr.lozan(a)volny.cz _______________________________________________ ECI-EN mailing list ECI-EN(a)lists.transmedia.de http://lists.transmedia.de/mailman/listinfo/eci-en