PUBLIC MARKS with tag contraste

Extension Inkscape simulant les différents problèmes de perceptions des couleurs

Low-contrast fonts and unreadable texts? To hell with them!

The toolbar enables developers to examine WAI-ARIA live regions roles and properties, examine data tables, and determine if the colour contrast is sufficient.

The application allows users to experiment with color combinations, examine them under the aspect of accessibility guidelines and to create custom color palettes.

This service has been provided to allow you to check the validity of your CSS against the W3C's validation service, along with a colour contrast test, and a test to ensure that relevant sizes are specified in relative units of measurement. If the CSS is specified by a URL, it will be loaded into the text area to offer an option to make changes for testing without having to re-upload.

The Colour Contrast Check Tool allows to specify a foreground and a background colour and determine if they provide enough of a contrast "when viewed by someone having color deficits or when viewed on a black and white screen"[W3C]. The tool will indicate that the colours pass the test if both the colour difference and the brightness difference exceed their threshold. It will indicate that it sort of passes if only one of the two values exceed their threshold. And finally, it'll fail to pass if neither value exceeds its threshold. The tool will also indicate if the colours pass the newer WCAG 2.0 contrast ratio formula. The WCAG 2.0 formula differentiates between text smaller than 18pt text larger than 18pt (or text that is bold and larger than 14pt). For AA compliance, text should have a ratio of at least 4.5:1 (larger text, at least 3:1). For AAA compliance, text should have a ratio of at least 7:1 (larger text, at least 4.5:1).

Passe en niveau de gris un site pour en apprécier les contrastes

Le peintre Suisse Johannes Itten, (1888-1967), professeur du Bauhaus de 1919 à 1923 est à l’origine d’une reflexion sur les couleurs. Il a défini sept types de contraste de couleurs que nous allons passer en revue ensemble.

Version française : http://blog.britoweb.net/post/2008/11/18/Nouvel-outil-de-verification-du-contraste-des-couleurs