[argyllcms] Question about DeltaE from printread and one about iccexamin/profcheck

  • From: "Lars Tore Gustavsen" <lars.tore@xxxxxxxxxxxxxx>
  • To: argyllcms@xxxxxxxxxxxxx
  • Date: Mon, 10 Sep 2007 18:02:33 +0200

Another long question. Basically I ask what can explain a high
printread DeltaE, and a question about differences between profcheck
and iccexamin.

Yesterday I printed an RGB 528 patch target. When I read it today with
printread I got this warning when I tried to read two of the strips:

About to read strip pass F

Trigger instrument switch or any key to start, Esc, ^C or Q to give up:

There is at least one patch with an very unexpected response! (DeltaE 82.860992)

Hit Return to use it anyway, any other key to retry, Esc, ^C or  Q:

After I reread the same row a few times I hited enter and accepted
this. Maybe it would be more correct to trash  the target and start
over again?  Or can this be related to question I asked a month ago
about printtarg and DeltaE. I think the DeltaE that printarg reported
on this target was about 90% after optimization.
Anyway, afterwards when I build the profile I got this messages:
 profile -v -D"RGB-luster test4" -qm -S sRGB.icm -cmt -dpp test4

profile check complete, peak err = 7.405302, avg err = 1.056087

I then played with different text utility  and deleted all
measurements in the ti3 file from row F. I then got  this result when
I made the profile without the F row.
profile check complete, peak err = 7.345448, avg err = 1.044123

I guess this mean that that this patch is skipped in the profile
creation? I tested the profile on a PDI target and I am actually very
please with what I saw.  I just wonder what can be wrong with my
target. Can there be a patch outside the printers gamut?

I tried so to identify this patch. If I take a look at the output from
profcheck from row F the one with highest Delta E is patch 6:
Profile check complete, errors: max. = 7.405302, avg. = 1.056087, RMS = 1.331468

 [0.571890] 1.000000 0.000000 0.000000 -> 50.490826 70.709652
65.121628 should be 50.464170 70.820274 64.561172

However icc_examin gives me this result for the profile:
 averaging deviations (dE CIE*Lab): 36.5161 maximum: 67.1216 minimum:
0.739298 (dE CIE 2000) averaging: 14.9649 maximum: 21.93 minimum:
and patch 6
dE Lab dE2000
46.638 12.9499
Take a look at  http://www.mulebakken.net/div/iccexamin.html for a
more readable  cutted down iccexamin report for row F only.

For me this is quit confusing, but I guess there is a explanation on
this. The differences on the reported Delta E  on the patch from 0.5
to 46 is quite big.  And for the whole file difference between avg
error 1.04 to 36.52 is quite big. Can someone pleas teach  me?

(Kai-Uwe, there was a bug in iccexamin that don't allowed me to save
the report if the html file not existed)

Where can I put the  DeltaE 82.860992 that printread talks about in
this landscape.

Lars Tore Gustavsen

6 "F5" 100.00 0.0000 0.0000 41.830 22.052 2.9132

6 100.00 0.0000 0.0000 35.186 18.810 1.2915 50.464 70.819 64.561

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