Web pages shall be designed so that all information conveyed with color is also available without color, for example from context or markup.
G18 Ensuring that a contrast ratio of at least 4.5:...
The objective of this technique is to make sure that users can read text that is presented over a background. For Success Criterion 1.4.3, this technique describes the minimum contrast ratio for text that is less than 18 point (if not bold) and less than 14 point (if bold). For Success Criterion 1.4.5, this technique relaxes the 7:1 contrast ratio requirement for text that is at least 18 point (if not bold) or at least 14 point (if bold).
If the background is a solid color (or all black or all white) then the relative luminance of the text can be maintained by making sure that each of the text letters have 4.5:1 contrast ratio with the background.
If the background or the letters vary in relative luminance (or are patterned) then the background around the letters can be chosen or shaded so that the letters maintain a 4.5:1 contrast ratio with the background behind them even if they do not have that contrast ratio with the entire background.
The contrast ratio can sometimes be maintained by changing the relative luminance of the letters as the relative luminance of the background changes across the page.
Another method is to provide a halo around the text that provides the necessary contrast ratio if the background image or color would not normally be sufficiently different in relative luminance.
When a web page requires that an applet, plug-in or other application be present on the client system to interpret page content, the page must provide a link to a plug-in or applet that complies with §1194.21(a) through (l).
6.3.8a All pages that have links to files that require...
This checkpoint may require customization.
Text indicating where to download required special reader for PDF files is not present.
1.6 Validate that the alt text does not use the tex...
When users add alternative text to an image they tend to add the word "Image" when it really says nothing about the image, but describes the object versus the meaning of the object. This check will fail a page for the use of the word image in the alternative text.
Image Alternative Text should not contain the text "Image": Alt="Data-Driven Leadership (0470594799) cover image"
Row and column headers shall be identified for data tables.
H73a Use the summary attribute of the table element ...
The objective of this technique is to provide a brief overview of how data has been organized into a table or a brief explanation of how to navigate the table. The summary attribute of the table element makes this information available to people who use screen readers; the information is not displayed visually.