Bonjour
Je m'interroge -je ne suis pas un connaisseur ;) - sur la possibilité de
bénéficier d'une correction
colorimétrique sur l'ensemble de l'écran, c'est-à-dire indépendamment de la
capacité de tel ou tel logiciel de
gérer les profils ICC. Je m'étais convaincu du contraire (c'est-à-dire que le
profil doit être chargé au
niveau du système d'exploitation, pour correction du gamma, ET au niveau du
logiciel de traitement, pour
l'équilibre des couleurs), jusqu'à ce que je lise le manuel du Gnome Color
Management System (Fedora), qui
semble sous-entendre le contraire... je reste donc perplexe.
Quelqu'un aurait-il une idée sur la possiblité de bénéficier d'une calibration
malgré un logiciel ne gérant
lui-même pas les profils ICC (Cinelerra, Kdenlive), en déléguant la correction
à X ?
Le passage incriminé du manuel:
>
> "5.1 What's the difference between calibration and characterization?
>
> Many people are initially confused about the difference between calibration
> and characterization.
> Calibration is the process of modifying the color behavior of a device.
> This is typically done using two mechanisms:
>
> 1.
> Changing controls or internal settings that it has.
>
> 2.
> Applying curves to its color channels.
>
> The idea of calibration is to put a device is a defined state with regard
> to its color response.
> Often this is used as a day to day means of maintaining reproducible behavior.
> Typically calibration will be stored in device or systems specific file
> formats that record the device settings or per-channel calibration curves.
>
> Characterization (or profiling) is recording the way
> a device reproduces or responds to color.
> Typically the result is stored in a device ICC profile.
> Such a profile does not in itself modify color in any way.
> It allows a system such as a CMM (Color Management Module) or a color aware
> application to modify color when combined with another device profile.
> Only by knowing the characteristics of two devices, can a way of
> transferring color from one device representation to another be achieved.
>
> Note that a characterization (profile) will only be valid for a device
> if it is in the same state of calibration as it was when it was
> characterized.
>
>
> In the case of display profiles there is some additional confusion because
> often the calibration information is stored in the profile for convenience.
> By convention it is stored in a tag called the vcgt tag.
> Although it is stored in the profile, none of the normal ICC based tools
> or applications are aware of it, or do anything with it.
> Similarly, typical display calibration tools and applications will not be
> aware of, or do anything with the ICC characterization (profile) information.
>
> 5.2. Missing information for whole-screen color correction
>
>
> Unfortunately, many vendor-supplied ICC profiles do not include the
> information required for whole-screen color correction.
> These profiles can still be useful for applications that can do color
> compensation, but you will not see all the colors of your screen change.
[Et si, au contraire, les infos nécessaires sont présentes ?]
>
>
> In order to create a display profile, which includes both calibration and
> characterisation data, you will need to use a special color measuring
> instruments callled a colorimeter or a spectrometer."
Merci de votre patience
Quentin
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