[argyllcms] Re: Conversion omitting/locking device colorant

  • From: Graeme Gill <graeme@xxxxxxxxxxxxx>
  • To: argyllcms@xxxxxxxxxxxxx
  • Date: Sun, 11 Jan 2009 21:06:36 +1100

Martin Weberg wrote:
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?

Yes, the latter. The former won't work, since various things will fail
if the device response doesn't occupy space in CMYK and PCS.

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.

Yes, if speed is no object, then it's possible to write inversion
code with different objectives.

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?

It's either root finding or minimisation of an objective function.
Naturally there are both these sorts of routines in Argyll itself :-)

Graeme Gill.

Other related posts: