Re: [Lcms-user] Re: [Lcms-user][OpenICC] vgct tags

[<co...@do...>]

>> I have to add a very important item: The profiles, created with
>> ProfileMaker, basicccolor display, Monaco, ... do include the vcgt and
>> are not containing valid device characterization if the vcgt is not
>> taken into account. This does mean, that an ICC-lib should support

> This is an OS issue. Independent of an CMM.

>> vcgt tags, as they are required to correctly apply the data of
>> these profiles (which are most likely the majority).

> Again an OS issue. The profile attached to an screenshot image is 
> completely valid in the sense of the ICC spec. Why would someone need the
> linearisation data of an printer, With the Cmyk ICC profile a separated
> image is completely described, as it can be converted to pcs.

What I wanted to say is simply: You should not ignore these tags
completely, since they are accidentaly very powerful. E.g. changing
the whitepoint with a vcgt tag is fairly easy, so don't apply it and
all data contained in the profile is invalid.

You are right in terms: it's the responsibility of the OS to apply
these changes. But there's no better/cleaner way for now to say that
certain calibration data lead to a certain profile (at least it's the
impression when looking at all the commercial profilers).

Stefan

-- 
Stefan Döhla
mailto:co...@do...