[argyllcms] inter-instrument matching tables
- From: Roberto Michelena <colorsync@xxxxxxxxx>
- To: argyllcms@xxxxxxxxxxxxx
- Date: Tue, 8 Nov 2011 09:02:36 -0500
Hi all,
I'm wondering if at least for the limited purpose of proof
validation/certification, a way to "match" various instruments to a
"master" one can be devised. On just a certain paper/ink combo (a
single paper, various printers but same inkset - i.e. Epson 3880, 4880
and 7880).
I make my iterative proof calibration (Oris ColorTuner) with a DTP-70
; to a very good match (typical 0.5dE avg, 3.5dE max).
But then to check proof stability/validity over time, the customer
might use an i1, or even worse, i1-uvcut. From the very first day, if
they try validate a proof (typical validation strip 12647-7, 54
patches) it will yield quite different numbers, maybe even out of
tolerance.
So my plan:
1) in the same style as Idealliance does with their G7 graybalancing
target, build some target (large, maybe 8000+ patches) that can be
read with all instruments (iSis, i1, DTP-70)
2) print one specimen of that target, linearized/maxgamut on the
intended printer/inkset and paper combo.
3) measure that one specimen with all involved instruments (the
individual instruments, not the model) - so let's say measure in a
handful of i1's, one DTP-70, one iSis, and a few i1-uvcut ones.
(output only Lab/XYZ, no spectral needed)
4) make some sort of "Lab-to-Lab" link profile for each instrument to
"match" the master one (DTP-70).
Then, for proof validation, measure through the individual instrument
(ie i1 #2), apply the relevant "instrument correction" profile to the
measurements (i1#2 correction), and then use those corrected
measurements for a validation that would be closer to the one that
would have been made with the "master" instrument (DTP-70).
Sounds feasible/useful?
(as long as a canned validation software is not used, but just
ColorPort or some other measurement software, coupled with an Excel
spreadsheet).
What should I use to create the "correction link profile" (Lab to Lab)
when I have the set of two measurements (master and individual) to be
corrected?
As long as it's restricted to one paper/inkset combo, will it be
useful even to uvcut instruments?
-- Roberto Michelena
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