Évaluez les couleurs et la luminosité de votre image à l’aide des conditions d’affichage recommandées par ISO 12646:2008.

When developing an image, the way we perceive brightness, contrast and saturation is influenced by the surrounding ambient conditions. If an image is displayed against a dark background, this can have a number of adverse effects on our perception of that image:

  • Exaggeration of the perceived exposure makes the image seems brighter than it really is. This is nicely illustrated by the Adelson checkerboard shadow effect .
  • A decrease in the perceived saturation in the image makes the colors seem less rich than they really are (the Hunt effect).
  • A decrease in the perceived contrast in the image makes the tones seem flatter than they really are (Bartleson-Breneman effect 3)

Il en résulte que l’image finale peut être trop sombre et mal développée en termes de contraste et de saturation des couleurs. Pour éviter cela, la norme “ISO 12646:2008” fait quelques recommandations sur les conditions dans lesquelles les couleurs d’une image doivent être évaluées. Le module évaluation des couleurs de la chambre noire place un cadre autour de l’image pour aider l’utilisateur à mieux évaluer les couleurs de l’image dans le sens de ces recommandations.

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When the color assessment button

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is selected in the bottom panel, the image is zoomed out so that a thick mid-gray border appears around the image to act as a reference against which to compare the image’s tones. A thinner white border is placed immediately around the image to give the eyes a basis for comparison when looking at parts of the image that are meant to be a bright white.

Although the color assessment mode provides a mid-gray surrounding to the image, it is recommended that you also set your user interface (in preferences > general) to one of the “grey” themes. These themes are designed to provide a user interface that is close to middle gray (it is actually slightly darker to allow better contrast with the text in the user interface). When one of these themes is used together with the color assessment mode, this will help to avoid the above perception issues.

Le mode évaluation des couleurs peut également être activé/désactivé en appuyant sur Ctrl+B.