Re: SWOP Proof Certification, TRxxx Characterization Data
Re: SWOP Proof Certification, TRxxx Characterization Data
- Subject: Re: SWOP Proof Certification, TRxxx Characterization Data
- From: Klaus Karcher <email@hidden>
- Date: Wed, 29 Oct 2008 11:15:48 +0100
Roger Breton wrote:
... I could not understand what the bar height
represented. [...]
I could not get over this concept of "percentages".
And then, while reading your exchange with Mike, above, it suddenly became
clear that the percentages represented the ratio of the actual DeltaE to the
Max DeltaE acceptable.
Exactly.
What is the advantage of using such a representation?
Percentages are more suitable to judge the meaning of these Delta E /
Delta H figures.
Imagine your Fogra Media Wedge evaluation results in:
DE max measured = 2.20
DH avg CMY-gray meas. = 0.96
this information is not really useful until you know their context, i.e.
the tolerance limits:
DE max acceptable = 6
DH avg CMY-gray acceptable = 1.5
but even then it's still difficult to judge these numbers as they are on
different scales.
But when one knows that the proof bails out
2.2 / 6 = 37% of the tolerance range for maximum color difference and
0.96 / 1.5 = 64% of the tolerance range for average hue distances of
composed grays, even a layman will get the idea that the max DE of this
proof is less problematic than its gray balance error.
Here is a plot containing Fogra Media Wedge v2 evaluations for four
different proofs,
Allow me eine frage: is it fier different proofs from the *same* proofing
system?
No.
- Proofs 1 and 2 are from the same proofing system (EPSON9600/GMG/GMG
Proofing Paper). The data for Proof 2 went through a Colorserver
(PuzleFlow ColorManager) before.
- Proofs 3 and 4 are from another proofing system (EPSON9600/EFI
Colorproof XF/Fuji IPP-SG proofing paper) on two successive days.
The differences between Proof 1 and 2 were visible in critical areas.
The differences between Proof 3 and 4 did not become noticeable.
The differences between Proof 2 and 3 were inadmissible for the client.
The differences between Proof 1 and 3 were less severe, but still
inadmissible.
(It was about a very color-critical jewelry/beauty Job)
The black error bars equate to the reproducibility for this two devices:
How does one interpret the "reproducibility"? [...]
Is that the average of 10 readings on the same patch? Or do you
mean inter-instrument agreement? Sorry, it is not clear to me :(
inter-instrument agreement, investigate on a large number of
measurements, printed on both systems.
P.S. Maybe the vertical axis should not have values higher than 100%?
... as soon as there are only valid proofs all over the world ;-)
Klaus
--
Klaus Karcher * Eichenallee 18
26203 Wardenburg * Germany
Tel. +49 441 8859770
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