Re: Epson 5500 Metamerism
Re: Epson 5500 Metamerism
- Subject: Re: Epson 5500 Metamerism
- From: Scott Gregory <email@hidden>
- Date: Thu, 30 Aug 2001 19:53:57 -0400
I've been on the sideline for a while now looking for a good opportunity to
jump in so here's my 2 cents worth. Color matching with a device that uses
a dye set that's susceptible to Metamerisms can be quite tractable. The
issue is in the details of how you determine what you are matching from and
to.
The problem today is there is no easy and accurate method for factoring in
the actual illuminant that the media you are profiling is being viewed
under. Most profiling applications use the spectral power distribution of
D50 to calculate the tristimulus values and the subsequent LAB's, not an
illuminant close to the actual viewing condition. This won't reduce a
media's susceptibility to metamerisms but it does enable matching under
different illuminants. Knowing the characteristics of the ultimate viewing
condition is essential to communicating the correct color.
Getting the correct amount of UV factored in can also be important but more
times then not using the wrong illuminant in your spectral integrations will
lead to much larger errors.
As you can imagine using this additional degree of freedom required to
manage output color correctly creates another challenge for managing an ever
growing database of profiles. In order for profile selection not to be
rocket science, we need a better solution for building, identifying, and
ultimately compensating an output profile.
The ICC has a viewingConditionsType tag which is a start IF profile building
vendors and profile applications used it. The tag does fall short of
actually communicating the viewing illuminant spectrum and some dye
characteristic information. This could be used to at least do a first order
compensation for the effect of different illuminants.
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Scott Gregory
Principal Consultant
Adv. Color Management Solutions
mailto:email@hidden
781.275.1033
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