Datacolor User to User Support Group.

>David,
>
>Thank you for your offer of help, but I finally managed to produce
>two profiles that are vastly better than anything I've managed before.
>
>I used the 3-page 729 chart.
>
>I can't understand why both smaller charts would be such a problem
>for me. The 150 patch version is *much* easier to read, and I
>wouldn't have thought that my printer and/or inks would be strange.
>I'm using an Epson 2200 with MIS Pro ink.
>
>There is no need to answer this email.

But how can I resist...? :-)

I would recheck your prints of both the lower-res patch targets. (Based
on recent postings here, it's possible that you may have printed them
incorrectly at the start, which is where the fussing and tweaking may
have come from).

Paul Nieuwenhuize found that all of the tweaks he'd needed to make to
get marginal results on his Epson were due to the fact that he'd been working
from a target print that had -not- been printed with color management disabled.
(And even with this, it really wasn't possible to get good results).

If your tweaking is more than a couple of points on more than a couple of
sliders, then I'm suspicious of your target prints. Paul, if I recall,
had to push brightness to +18 to get a print that looked -somewhat- OK. This
was because his target measurements (coming from a target incorrectly printed
through a profile!) were too light (and color, saturation, and other things
would have been wrong, too, but we'll just worry about brightness for now).
The profile built from these wouldn't compensate properly for later printing;
usng the newly built profile; when color management WAS properly set up during
printing. With sliders at 0 during profile building, this would have produced
a print that was much too dark; brightness +18 mostly compensated for that;
but overall the results still wouldn't be good, because the measurements
of "profiled" color patches won't accurately reflect the gamut of the printer.

The 150 and 225 patch targets contain measurements for 9 evenly spaced grays.
The 225 patch target also has additional measurements in the highlight and
shadow areas. These -should- be enough to give you good results when print
neutrals and near-neutrals in an RGB image.

The 729 patch target has many other measurements for -color- patches, but
still contains only 9 grays. There shouldn't be a substantial increase in the
quality of these prints based on going to the 729 patch target, as far as
what you're talking about; I'd expect to see subtle differences, but not
"vastly better" differences. Overall improvements you might expect from the
729 patch targets have to do with color more than anything else, rather than
grays.

So, if you have time, I'd suggest doing one more test: carefully reprint the
225 patch target and measure it. Keep the older set of measurements around,
give these a new name, so that you can compare. Toggle back and forth between
both sets in the PFP UI screen; do you see things noticeably change? (You
shouldn't, if both targets were printed the same way). If things shift, then
if the new target print is "right", then the old one was "wrong". Try building
through the new set of meausurements and see what you get.

-- 
David Miller
Senior Software Developer, Digital Color Solutions
ColorVision