[argyllcms] Re: Conversion omitting/locking device colorant
- From: "Martin Weberg" <martin.weberg@xxxxxxxxx>
- To: argyllcms@xxxxxxxxxxxxx
- Date: Sun, 11 Jan 2009 08:23:40 +0100
On Sun, Jan 11, 2009 at 05:38, Graeme Gill wrote:
> No, this sort of colorant sub-setting isn't really supported,
> because the assumption that the user is after maximum gamut
> from a profile, is built into the inversion code. While it
> may be possible to play some games with the ink limit equation
> to eliminate parts of the gamut containing unwanted colorant
> combinations, I'm not sure how well this would work without trying it.
>
> For some combinations you might get away with choosing a sub
> set from your test colors, and creating a profile out of
> that reduced set (ie. if you just use CMY samples with K=0,
> then create a CMY profile, the you can lookup CMY K=0 values, etc.),
I could try this. Stripping the FOGRA39L data of all combinations
using K except for K=0. Then create a CMYK profile. Or should I also
strip the entire CMYK_K column creating a CMY-profile?
Then I guess there is a possibility with an iterative process finding
the closest match (using i.e. dE2000). Like, feeding icclu with a seed
(educated guess) sub-set of the device color and then compare the
resulting Lab color with the reference Lab color. The process proceeds
exploring nearby sub-set device colors and chooses the "path"
resulting in minimum dE. There is a possibility with different results
depending on the seed.
Studying marine biology I did a simulation lab using this sort of
thing. Just can't remember what the process/algorithm is called.
Maybe, you know a way of doing this?
Martin Weberg
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