[Openicc] meta data in test chart

[edmund ronald]

Grame,

 I defer to your great expertise in color management. However it seems
to me that the CLASSIC ICC profile scenario has as one great design
weakness (among others) precisely the fact that the source gamut is
NOT known prior to gamut mapping, as far as I know.

The reason for this design decision is -as I have come to understand
it - is partly that for press applications, one does not wish to have
adaptive mappings because they would destroy the coherence of work
contributed from different source gamuts. Fine arts printers and
photographers may have different opinions, but it would seem no one
asked them.

Edmund



On Mon, Jan 24, 2011 at 1:57 PM, Graeme Gill <graeme at argyllcms.com> wrote:
>
>> The system above is actually not a bad design, but it would be even
>> better provided the handoff space were ProfotoRGB (very wide gamut)
>> or PRNG (all printable colors), and a 16 bit conversion were
>
> I'm not sure that's a good idea with current workflows. The reason
> is that few if any workflows have, or communicate the concept
> of an image gamut. Unlike other smaller gamut color spaces, where
> typically the image has been rendered to just fit into that space,
> and therefore the colorspace gamut is a reasonable guide to the image gamut,
> a very wide gamut space like ProPhoto or L*a*b* cannot be used
> as a guide, because the images gamut will almost always be a great
> deal smaller than the space it is encoded in.
>
> The reason this is important is gamut mapping. If an image is to
> be mapped well into the destination colorspace, the gamut it
> occupies needs to be known or anticipated. If the encoding colorspace
> no longer provides that information, where does it come from ?
>
> Graeme Gill.
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