Re: Uniform Perceptual Lab space
Re: Uniform Perceptual Lab space
- Subject: Re: Uniform Perceptual Lab space
- From: Henrik Holmegaard <email@hidden>
- Date: Wed, 25 Feb 2004 08:23:19 +0100
Tim Vitale <email@hidden>
>The discussion on its use describes the problems
>that I have been having with printer output. Saturated blues go
purple,
>saturated reds go orange and images with little more than shades of
>yellow are under saturated.
If you read the PostScriptum on Color Management, non-linearity is
referenced as an attribute of all current CIE models. When a gamut
mapping is developed, it has to take these visual non-linearities into
account. It may be that more advanced approaches will become available
if the ICC changes the definition of the Profile Connection Space, but
for now things work well if the measurements are correct, if the
printer profile does the corrections it is supposed to, and if the user
sets the right rendering intents in the application software. The
definition of the PCS is a political issue, and with it the position of
future appearance models. There is one camp which roots for a PCS
geared to the print and another camp which roots for a PCS which also
looks to the screen. The membership of the ICC appears to have split
over this, if I have got things roughly right. For practical purposes
it does not matter as the current drive is for remote proofing through
the OutputIntent in PDF (which means a spring cleaning of proprietary
RIPs that do not support the ICC profile file format or the
OutputIntent construct). The image design studio, the page design
studio, the prepress studio and the press room need to be linked up
with colorimetric color tolerancing, and for that we simply need sound
sense and a spectrophotometer.
Thanks,
Henrik
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