RE: CMY Display coming?
RE: CMY Display coming?
- Subject: RE: CMY Display coming?
- From: Roger Breton <email@hidden>
- Date: Sun, 09 May 2010 23:11:30 -0400
Marco,
To me, the more similar colorants are, spectrally, the less metameric they need to be in order to obtain a good match. The ideal case is a spectral match, with two colors matching perfectly under all illuminants because the underlying colorants from which they're made are exactly alike. On the other hand, the less colorants are alike, in my mind, the more "metameric" the match becomes. I think that with inkjet proofs and press inks, the match will always be metameric. Same with laser proofs and press inks because the underlying pigments don't have the same spectral shape, so it is impossible to obtain spectral matches between these kinds of systems. I think we would always want less metameric matches but that's impossible, especially between RGB and CMY.
In principles, the way I understand this, black ink was added historically to CMY to compensate for ink's departures from the ideal, the so-called block-dye behaviour, that each ink would absorb its theoretical part of the spectrum. In fairness, I don't know to what extent it is technologically possible or necessary to obtain such perfect behaviour with CMY filters in order to obtain a good reproduction.
As for what exact spectral shapes these CMY filters exhibit, I can't say for sure until I get a chance to dig out the article in question. It may have been in one of the Powerpoint slides during the presentation.
Sorry my memory can't retrieve this information better for now / Roger
>
> What would "less metamerism" mean in this context? Metamerism is a good
> thing, as it allows to match colors between two specimens using spectrally
> different components with a given illuminant. So, if anything, wouldn't one
> would want MORE metamerism, meaning more of a MATCH between two
> metamers of different spectra?
>
> >for it is not trying to mimic the tristimulus values of a print system with
> >a physical stimulus that has no relationship to the real thing since
> >it is using spectral filters that closely espouses those of the real
> >inks. To me, that's the real difference.
>
> Well, perhaps so, but I still don't see how the system would duplicate the
> spectral filtering properties of the "real inks" by just matching C, M and Y and
> not K. I just haven't read a convincing explanation of that yet.
>
> It seems to me that my 4 earlier questions are still unanswered, in particular
> the one regarding WHICH exact print specification these CMY "ink-like filters"
> would be intended to duplicate (arguably, at the expense of duplicating
> OTHER print scenarios).
>
> Marco Ugolini
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