[Lcms-user] How to correct wrong black-point

[Tamas L. <lit...@gm...>]

Hi,

I encountered a strange working behavior of my X-Rite i1 and don't know how
to solve that problem..

We have a new small size photo printer in our shop which uses a special dye
ink.
I usually do my own calibrations instead of using those ones that come from
the manufacturers and 99% of my profiles work as I expected. Except for
this printer.

Manufacturer's profile has some serious shadows (disadvantage) that I don't
like, but the blacks are 99.9% black (advantage).
My profiles have a much more linear response without that shadow
(advantage), but the blacks always have some color tints in it - like a
little bit greenish - compared to "real" blacks. The manufacturer's profile
can "guess" this black, but i1Profiler cannot and I don't know the reason
why. Because i1Profiler performs well on other types of paper and printer,
I think it's caused by a bad combination of photo paper and dye ink type.
(My first guess was the high OBA content, but the OBA Calibration mode in
i1Profiler had similar results.)

What can I do with it?

I also don't know how we can define the grays & blacks, what is an exact
gray without (or a min.) color components included....

Is there a way to move my "wrong" calibration to the right direction? How
can I measure the exact distance for it...? Not only in theory, but
programmatically, too (I am familiar with lcms). Is it the right path to
solve the problem?

Any ideas or help welcome!

Thanks!
Tamas