Re: Rel vs Abs proofs
Re: Rel vs Abs proofs
- Subject: Re: Rel vs Abs proofs
- From: Terry Wyse <email@hidden>
- Date: Wed, 11 Oct 2006 17:00:58 -0400
I'll offer a counter argument and say that you may be on to something
Roger. In theory (and reality if you believe what ColorShopX is
showing me), the gamut will expand by whatever amount the paper white
happens to reduce the gamut (I'm thinking of an increase in chroma at
this point) in absolute rendering. When the paper white goes from,
for example, L*90 to L*100 in relative, everything should get a bit
lighter and more saturated/chroma. ColorShopX is showing that to me
if I switch between abscol and relcol. So in theory Roger, the relcol
"proof" you get will not only have whiter whites but increased
saturation in the solid primaries/secondaries as well.
The REALITY is, however, that much of this gamut expansion gets
eliminated by the proofing media. Whatever gains there were by
"zeroing out" the press stock to white gets reduced back to the paper
white of the proofing media. Assuming the proofing media is whiter
than the paper white in the press profile, you'll still get SOME
expansion but probably only about 1-2 L* worth depending on the
difference between proof media and press paper white.
Terry
On Oct 10, 2006, at 9:28 PM, Roger Breton wrote:
Sorry to bring this one to life but I think I'm bringing new
information to
the table, hoping to spur more discussions on the impact of each
rendering
style.
In hardcopy proofing, there are two schools of thoughts regarding
appropriateness of proofing intent. There are those that advocate
relative
colorimetric at all costs and those that advocate absolute
colorimetric at
all costs.
Ignoring the effect of UV and other optical phenomenon, with
AbsCol, the
colorimetry presented to the viewer in the form of the proof
(Destination),
matches the colorimetry measured by the originating instrument
(Source).
That's by the ICC specs.
With RelCol, the colorimetry presented to the viewer does not match
the
originating colorimetry (Source) but is rather "adapted" to the
white point
of the hardcopy output (Destination) thereby preserving the "relative
appearance" of the Source.
Would it make sense to argue that, in RelCol, users nevertheless
expect the
RelCol of their harcopy proofs to be matched absolutely?
Discounting the
absolute white point of the proofing substrate.
Last but not least, this is more of a printing-related type of
question,
would it make sense to argue further that, in order to match a
RelCol proof,
as compared to match an AbsCol style of proof, everything else being
constant, a printing press will have to expend more ink? Because
the colors
to be matched are, for all intents and purposes, more saturated?
A client of mine recently made the switch from AbsCol proofs to RelCol
proofs and I have the distinct impression that, in order to match
this new
generation of proofs, the press needs to expend more ink, all of a
sudden.
Is that consistent with anyone's experience?
Roger Breton | Laval, Canada | email@hidden
http://pages.infinit.net/graxx
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