So far in our noble quest to make WCAG 2.0 understandable, we’ve discussed a number of ways to provide alternatives to content on your site that would otherwise be difficult for those experiencing visual or auditory impairment to understand, such as alt text, captioning, sign language, and audio descriptions. The set of guidelines in WCAG 1.4 ‘Distinguishable’, on the other hand, will show you how to make the content on your site more easily seen and heard without making many significant alterations.
This point is a bit similar to WCAG 1.3.3 Sensory Characteristics. Whereas that item highlighted the importance of not using visual or audio cues, such as colors, shapes, or sound, as the sole means of conveying information, WCAG 1.4.1 talks about the problem with using differences in color to indicate content. If your site requires users to distinguish between colors in order to navigate or understand the content featured there, those experiencing visual impairment may have a difficult time utilizing it.
Let’s return to that survey example we discussed in WCAG 1.3.3. Imagine that you created a survey containing both required and optional fields. You colored the text prompts for all required fields blue and indicated as much to users in the instructions at the beginning of the survey.
Since someone experiencing visual impairment may not be able to distinguish between required and optional fields based on color alone, you should include text cues such as “(required)” or “(optional)” following the appropriate field prompts in order to make the survey clearer. Please note, as with WCAG 1.3.3, you do not need to do away with instances in which you use color differences to convey information, since those experiencing cognitive limitations may find them useful.