On 7 Mar 2017, at 10:45, Malcolm Mackenzie <mm@malcolmmackenzie.co.uk> wrote:
I did a few tests in i1P and confirm your findings. The "Intelligent Black" feature does odd thing when it thinks TAC should be low and the Max K separation/width is contributing to the low yellow. I've had issues with the settings for digital as have others online. I remade the profile with the same data and it was fine, so it's an i1P thing. I've never got an answer or seen one from X-Rite on the issue.
Malcolm I also used ArgyllCMS and the results were the same, so I think that the Heidelberg software (or the operators) are editing out some of the FOGRA52 data. The neutral curves of the “official” profile have a distinctive relative intent shape at L30 where cyan exceeds black and yellow drops away. But the drop is only from 42.8% to 40.6% where it is artificially held in a straight line. i1Profiler and Argyll create high GCR profiles which max out with yellow somewhere around 15% which then drops to zero as the cyan values climb steeply. I think that the data either needs editing or an explanation of why the Heidelberg software is able to create a profile that can’t be matched by other profile making apps. The FOGRA51 data is isn’t much better either, but easier to spot why it’s problematic when it contains readings like this: c100.0 m100.0 y0.0 k100.0 = L11.43 a5.76 b0.01 c100.0 m100.0 y100.0 k100.0 = L12.71 a0.53 b4.89 Regards -- Martin Orpen Idea Digital Imaging Ltd