Contents are present with sufficient contrast compared to their background
Un bon contraste visuel est essentiel pour la lisibilité. It allows readers, including those with visual impairments, to easily distinguish text and images from the background.
Objectives
Allow a good readability of the content.
Limiter la charge cognitive lors de la consultation.
Improve accessibility of content to readers with disabilities.
Implementation
Ensure a minimum contrast ratio of 3:1 between text and background, as measured via WCAG2.0 algorithm
Control
Either upstream (at the time of the design of the digital book) : Repeating contents whose contrast/luminosite difference with their background is potentially insufficient; Use a tool like Colour Contrast Analyzer to calculate the contrast ratio : click on LuminoSitee and raise the color of the foreground and then that of the second plane in the defined fields; Make sure the contrast ratio is higher or equal to 3:1
Either downstream : Use ACE and its error report. Please check the case in the “Errors” tab and search for “color-contract”. Follow the procedure described above.