[argyllcms] Re: LUT versus XYZ monitor profile

  • From: Alexander <adfirestone@xxxxxxxxx>
  • To: argyllcms <argyllcms@xxxxxxxxxxxxx>
  • Date: Wed, 23 Dec 2009 01:39:49 -0800

> What I'll do for XYZ cLUT display profiles is to (by default)
> add a dummy set of matrix tags that produce an obviously wrong
> set of colors. This way it won't take any extra time to generate
> the matrix tags, and it will be obvious if the CMM is not using
> the cLUT. As an option I'll allow creating a valid set of
> matrix tags (although the white and black points will be from
> the cLUT, and so will not match the matrix model perfectly,
> hinting at more issues with trying to include both matrix tags
> and cLUT tags) for situations where a matrix fallback is needed
> (ie. different capability software can make best possible use of
> the profile).
> Graeme Gill.
Instead of the only options being 'obviously wrong' and '90% correct', how
would you feel about adding some presets to use the matrix tags from your
standard sRGB or Adobe1998 profile (or possibly a parameter to specify any
ICC profile with matrix tags) in order to simulate a more a 'neutral look'?
By 'neutral look' I mean a look similar to color management being disabled
(if your working color-space and image profile matched the tags you
attached). My logic being, this would give you a viewable image, unlike the
'obviously wrong' matrix tags without fooling yourself the image really is
being color managed accuratly with the '90% correct' matrix tags. Or is my
logic flawed in some way, and this won't work or is a really bad idea for
one reason or another?


That reminds me, Graeme, how would you feel about coding/releasing a
standalone tool which can add/remove/import tags to/from ICC profiles as a
nice complement to iccdump which can only read/export tags? From the sounds
of it you may already have a tool(s) written which can do some of these
things, since eariler you posted an ICC profile which you had removed the
matrix tag from, and colprof is obviously able to write tags to an ICC
profile. I don't believe any tool with those functions is publicly available
anywhere, so there is definitely a gap to fill. Even if the add/import
functions of such a tool only worked (i.e.created a valid output profile)
with Argyll created profiles, it would still be a valuable tool to have

What do you think? After you finishing up Argyll 1.1.0, give a go at
creating such a tool?
Too much work? Too difficult? Other concerns?

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