Re: Real world experience w/ GMG and Oris RIPs
Re: Real world experience w/ GMG and Oris RIPs
- Subject: Re: Real world experience w/ GMG and Oris RIPs
- From: Graeme Gill <email@hidden>
- Date: Wed, 01 Dec 2004 22:44:38 +1100
- Organization: Color Technology Solutions Pty. Ltd.
Mike Eddington wrote:
<2) The number of test patches isn't apples to apples. The iterative approach
used several times the number of patches to characterize the inkjet.>
Being iterative, it did use more measurements, but the the charts (patch count) were the same.
> Are you saying that if the ECI is measured say 4 times that in order to be apples to apples,
I should use 1485 x 4 patches for the non-iterative approach? If that's the case, I wouldn't be
able to test this as GMG only supports certain targets (ECI, IT8, TC4). Not only that, but
after the first iteration, values that are below the target delta E are not re-measured, so
the number of patches measured is less with each iteration and one would have to keep track
of the actual number of patches measured for each iteration in order to determine the size
of the chart the non-iterative approach needs (and since the iterative profile is based
on the non-iterative profile, there's a chicken-or-the-egg thing going on). One would also
then wonder if better results could be obtained by iterating the larger chart.
For a fair comparison as to the merits of an iterative vs. non-iterative approach,
the total number of patches printed and read has to be equal. With any reasonable approach,
printing and measuring more patches is going to improve accuracy and reduce errors.
The tools that GMG provide are (understandably) not set up to provide a fair
comparison, but concentrate on the approach that they think is going to work better.
I suppose there still is an open question as to whether results as good could be obtained
> with a larger initial test chart. The point of the test however, was to satisfy my curiosity
that colors outside the ECI patches were being competently adjusted and that there was more
going on than simply benchmark trickery. I think the test shows this.
Yes, I agree that there's no reason to think that other points outside the the
ECI test patches values have got worse, and lots of reason to think that they
have got better. I still think that using the same chart as was iterated
with, to numerically verify, has potential for being misleading.
Graeme Gill.
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