Re: ScannerRGB to WorkingSpaceRGB (rendering intents)
Re: ScannerRGB to WorkingSpaceRGB (rendering intents)
- Subject: Re: ScannerRGB to WorkingSpaceRGB (rendering intents)
- From: "Andre Schützenhofer" <email@hidden>
- Date: Wed, 11 Jul 2001 20:59:17 +0200
Robert wrote:
Andre, what is your "Source" profile when you concert colorimetrically
>with PBC On in Photoshop? And are you using ACE Engine?
Hi Robert,
I usually use ECI-RGB as workingspace, it refers i.e. to lightning
conditions/white point of D50/50000K and gamma 1.8, good for the Macs I use.
It is wide enough to cover all common CMYK-spaces and a little bit smaller
than the gamut of the IRIS proofer. So reference hard-proofs are possible.
Color Engine is Apple CMM, I do not use ACE because only Adobe Products ship
with it and it is not possible to select this CMM if additional workflow
renderings are necessary like in iQueue.
I completely agree with you if such a thing would be feasible.
Relative Colorimetric is the way to go. I never use Saturation. Although
you could say that all profile making software treat saturation
differently. In fact they do the same with Perceptual and Colorimetric.
I noticed PrintOpen 4 profiles don't care about saturation. When I select
saturation intent I use the perceptual LUTs who are "linked" to saturation.
I noticed too that relative colorimetric with BPC gives very good results in
PO4.
Joel wrote:
Users are entering larger and larger workspaces destined for smaller
>destinations and, in many cases, this is where perceptual has its
>strengths.
I think that's the point. The smaller the destination space the more
powerful becomes perceptual rendering and, in return, the bigger the
destination the more exact matching of source to destination is possible and
leads to colorimetric rendering relative to white and black, just like
perceptual does in always.
I noticed that the results of colorimetric rendering handled by different
profiles created by different programs are not as much as compared to
perceptual rendering. So the thing I have in mind is if anytime in future we
can deal with device-independent documents the results of i.e. remote
proofing can be very different just because different programs created
different profiles, even if based on the same measured data. This is not a
fault in particular, I think perceptual rendering can give excellent
results, but the results of sending out my RGB-data in order to gamut-map
perceptual to maintain best reproduction quality are then secret of the
profiling-program-manufacturers... :) <- not meant really serious. Just like
Neil wrote:
Let's take a step back, look at the numbers, and congratulate the
programmers who have given us the tools which let us make our images
portable within the limits of the chosen (1993? M.Stokes) limits that >we
use.
You're right. Without all this colormanagement stuff it would have been
definitively not possible to do a lot of work I did the last year.
regards, Andre Schuetzenhofer
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