Re: [Lcms-user] vgct tags

[Graeme G. <gr...@ar...>]

Marti wrote:

> lcms does currently NOT implement it because it is not on ICC spec.
> Alas, I'm a bit critical on such practices. Using this kind of stuff will
> make profiles "active" in the sense they are no longer a characterization
> of the hardware but a way to set specific configurations.

You're quite right about this. vgct is not the correct approach
to calibration. What should happen is that the profile should
contain the desired device response in the outputResponseTag,
and some separate system should calibrate the hardware to
make sure it meets the expected response for a given display
profile. This provides a mechanism to track device drift.

Unfortunately we're stuck with software systems that expect
the vgct tag to be present (Apple systems won't load the
profile if the tag is missing), even though it no longer
captures all the settings of a modern display system, such
as the monitor controls etc., and is the wrong information
to store in a profile ....

Graeme Gill.