Out Of Press Gamut (rewrite)
Out Of Press Gamut (rewrite)
- Subject: Out Of Press Gamut (rewrite)
- From: Bill Whitfield <email@hidden>
- Date: Fri, 23 Dec 2005 11:34:11 -0800
Greetings To All,
After reading some of the responses to my post and then re reading my
original post I realized that what I thought I had written as clear
and concise, was not.
Since I REALLY value the feedback I receive from this digest and
would like more feedback on these issues I will explain my challenges
(2) with more (hopefully) clarity.
Definitions:
Press Images Sheet - this is a sheet of images we printed on the
press after making the press profile.
Proof Images Sheet - same images file that was used to print press
images sheet. This was printed from the 4000 and then adjusted to
"match" the press images sheet.
Background review:
Flexo printer
DTP41 used to read ECI2002 target from press and proofer
EyeOne used to make spot measurements on images (press and proofer)
sheets
Profilermaker 5.02 used to make profiles (press and proofer)
Epson 4000 with Ultrachrome inks
Epson Proofing Paper Semimatte
Press paper is semigloss
Best v5.0 SP2
Both ECI2002 target and Press Images Sheet went through same workflow
Challenges:
1 - Proof images sheet does not match press images sheet. I received
some good suggestions for this challenge including; upping resolution
of proofer to 1440 x 720 (have already done that); trying different
papers (have tried one and have another on the way); and white point
adjustment (will try that upon return to the office after Christmas).
One other suggested covered TIL. I played around with that by adding
my own value in the TIL result box in the second step of Best RIP
linearization sequence. I do not have Best Premium so could only add
one number. I ran a cmyk ramp file through the uncalibrated queue and
discovered that the L value was lowest when all cmyk values were 88%.
I entered 352 in the TIL result box in an attempt to get more color
on the proof sheet (larger gamut?). But it did not seem to make much
difference when I built the subsequent proofer profile. I also
discovered that even though Best reports a 207 in the TIL result box
when I printed out the report and added the cmyk values listed on it,
the sum is usually in the 320 range. What is the 207 number all
about? By the way when I printed the ramp I was able to print 400%
ink without puddling.
In an attempt to make the proof images sheet match the press images
sheet I have iterated the profile, added a cyan curve and made 4
edits to the B to A table of the proofer profile. I have had limited
success as the colors are closer between the proof images sheet and
the press images sheet but still not close enough for me.
2 - Press images to press gamut problem. This challenge DOES NOT
include the Epson, only the press. One of the colors I am having a
big problem with when comparing press images sheet to proofer images
sheet is a light red (6% M, 17% Y). I measured this color, plotted it
in ColorThink and it is in the proofer gamut BUT it is floating above
the press gamut. If the parameters / tolerances to run the ECI2002
target used to make the press profile are the same as the ones used
to run the press images sheet how can this be? Parameters /
tolerances between two runs were; cmyk inks within .5 delta E, same
paper, correct densities, correct dot gain. While I could not find
the exact values (6% m, 17% y) in the ECI2002 target I did find
colors below these values so I would guess that I am not printing a
color on the press images sheet that the profile did not have a
chance to create by reading the press printed ECI2002 target. So with
my limited education I would guess that any cmyk color mix I
subsequently print on the press will fall within the press gamut, as
log as I honor the parameters / tolerances established when the
ECI2002 target was printed.
Thanks to all that take time to read this again and respond. I hope
it make mores sense and once again I apologize for my first attempt
to post this challenge.
-Bill-
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