[argyllcms] Re: General Questions

  • From: Graeme Gill <graeme@xxxxxxxxxxxxx>
  • To: argyllcms@xxxxxxxxxxxxx
  • Date: Mon, 24 Sep 2012 13:00:43 +1000

Michael Nagel wrote:


> (1) Is there a way to see a visual report of a correction matrix (similar to 
> a profile
> verification report) ?

ccxxmake reports the max and average fit error. Would it really be useful to 
separate out
this aspect as a verification function ?

> (2) Can this program write into the hardware LUT's of an Eizo CG275W ?

No, there is no current capability to write to specific display hardware.
I'd be pleased to add this, but no-one has seen fit to provide me with
the displays to RE and test, and I don't currently have the budget
to buy dozens of high end displays myself, and give the resulting
code away.

> (3) How can I change the adaptation method (Bradford, Cat02 etc.) ?

Which adaptation do you mean ? What benefits do you see in changing this ?

The ICC white point adaptation is hard coded as Bradford in icc/icc.c,
icmChromAdaptMatrix(). cLUT profiles B2A gamut mapping tables will use
CIECAM02 white point adaptation whenever a gamut mapping algorithm
using CIECAM02 is selected.

> In all my verification reports I see that the adaptation method was always 
> Bradford.

Yes. It seems to be the accepted best simple (ie. 3x3 matrix) white point
adaptation algorithm.

> (4) Can somebody advise on the ADVANCED GAMUT MAPPING OPTIONS ? What would be 
> standard default
> values to map to a gamut ?

I'm not sure what you mean. When creating profiles with gamut mapping, there
is a choice of pre-defined gamut mappings - see 
for instance. If you want to alter the gamut mapping details beyond this, then
you would need to alter the source code, ie. see the gammapweights tables in
gamut/gammap.c. Beyond that, you'd need to code your own algorithms.

Graeme Gill.

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