Contents are present with sufficient contrast compared to their background
As with photography, contrast makes the represented content more readable.
Objectives
Allow a good readability of the content.
Limit mental load during 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.