[argyllcms] Re: Calculate RAW importer profiles ?

  • From: Graeme Gill <graeme@xxxxxxxxxxxxx>
  • To: argyllcms@xxxxxxxxxxxxx
  • Date: Mon, 27 Jul 2015 23:57:38 +1000

Adriaan van Os wrote:


One could issue a warning if an image has a gamut that is not in the
test-range used.

You'd need a new custom tag to store a data structure to represent these
limits, as well as create an algorithm to generate it. This is not
easy in general, because gamuts defined by point clouds have arbitrary
boundaries if they are to occupy any volume. For the simpler case of
creating an enclosing gamut (which is what the ArgyllCMS tools use
when creating image gamuts), a modified Segment Maximum approach
is used with a convex hull in non-linear space. This encloses a good
deal more of gamut than the actual image, but this is not a problem
when the intent is to map the outer boundaries of the image gamut.
It took many months of development to get that to a useful, fast
and reliable state.

the occurrence of such an image implies there is fresh test-data and
therefore an
opportunity to improve the already calculated profile (assuming the camera
always produces
both a JPG and a RAW image).

Sure, but you've then defeated the purpose, which was not to use your
"reference" RAW

I tend to side with Anders in thinking that such development effort is better
into tools to achieve the look you want, rather that trying to imitate others.

Graeme Gill.

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