[Openicc] Color Management for Ubuntu

Graeme Gill graeme at argyllcms.com
Tue May 3 19:11:36 PDT 2011

Ann McCarthy wrote:

> Anyway -- this scenario should be handled under the basic rule of CM which
> is: "if the source profile of the content matches the profile of the
> destination THEN do not re-apply the destination profile." In my view an
> intelligent CMM should always apply that rule. So that is why I did not list
> it as a case of 'turn color management off'.

Hello Ann,
	this is actually a very bad way of disabling color management
that doesn't work in practice. This has been painfully proven by Apple.

It fails because it doesn't convey the correct semantics. The correct
semantics is that a colorspace is the devices space, whatever
that space is. Labelling the color space with the device profile
is difficult and fragile. It's difficult because you need to
somehow extract the exact printer profile from the printing system.
Such facilities may not be available to a remote system.
It's fragile because the printing system profile could change.

In fact if the printer settings are part of the profile and the
printing system automatically chooses a profile according to the
settings, it makes turning off color management even more fraught.
Consider: If you are trying to adjust the printer settings before
making a profile, this means that you won't know what profile the
printing system will use, because it probably won't have a profile
that exactly matches those settings!

The correct semantics are not in the nature of a profile match, but
a "wild card" match.


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