I printed and measured 101 neutrals, test image attached (also useful for monitor visual neutrals test). Discarded the first and last six patches as out of range for the paper, average dE2000 on the remaining 89 was .49, three patches over 1, all at the low end. Here are the first 15 dE2000 values:
L0 3.4733588
L1 2.5086567
L2 2.4167779
L3 1.5070952
L4 1.0084492
L5 1.3736149
L6 1.07466
L7 0.9987372
L8 0.8995739
L9 0.374725
L10 1.0301797
L11 0.3951753
L12 1.6917682
L13 0.3903298
L14 0.6377794
L* = 12 was the obvious worst at dE2000 = 1.69. I'm curious as to why the "bumpiness" at the low end, do profilers generally have trouble in this region?
I believe the profile should be good for printing anything, probably overkill for my humble Pro-100 but justifiable as this whole process has been educational for me. Thanks to Doug for his patch generator, and to both Doug and Mark for their helpful comments.
Richard Southworth
It's the Pro1000 printer Richard. The Pro1000 is in gamut down to L*=3 on glossy but the printer exhibits large changes in a* and b* from L*=3 to L*=25 or so. The variation is both large and, fortunately, smooth. Much smoother than my 9800 but the amplitude of the excursions on the Pro1000 was much more than the 9800. This, and improving the bumpiness of the 9800 at high L* was a major motivation to work on the tracking profile technique.
BTW, because of the really large excursions at low L*, setting the -s option to 10 instead of 2 should work much better on the Pro1000 neutrals. "-s 2" is pretty good for my 9800 but the Pro1000 needs a good tracking profile to reference for the "-s 2" to do work effectively.
Here's a graph of the Pro1000 raw device RGB on glossy that the profile has to correct. Max excursion is around L*=10 with a* going up to 6.9. The profiling software needs a high patch density in this area to improve.
As an aside, dE00 is much more sensitive to a* variation than dE76. A deviation of +1/-1 on a* produces about 1.5 dE00 v. 1.0 dE76.
