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Technique F81:Failure of Success Criterion 1.4.1 due to identifying required or error fields using color differences only

About this Technique

This technique relates to 1.4.1: Use of Color (Failure).

This failure applies to all technologies.


This objective of this technique is to describe the failure that occurs when a required field or an error field is marked with color differences only, without an alternate way to identify the required field or error field. This can cause problems for people who are blind or colorblind, because they may not be able to perceive the color differences that indicate which field is required or which field is causing an error.


  • A user is completing an online form, and the phone number field is required. To indicate that the phone number field is required, the label "Phone Number" is displayed in a color different from the color used for optional fields, without any other indication that "Phone Number" is a required field. A blind or colorblind user may not be able to identify that "Phone Number" is a required field.
  • A user submits an online form and leaves a required field blank, resulting in an error. The form field that caused the error is indicated by red text only, without an additional non-color indication that the field caused an error.


In both examples, the color could be used without failure if the text was sufficiently different in visual presentation (e.g. bold or in a different font) that it would be easily differentiated from the surrounding text if the color were removed. It would also not fail if the color chosen had sufficient luminosity difference (lightness) from the other text that it would be easily be seen as different if viewed in black and white. In these cases - the information would not be displayed in color (hue) alone but also in "presentation" or "lightness" respectively.



For all required fields or error fields in the Web page that are identified using color differences:

  1. Check that an non-color way to identify the required field or error field is provided.

Expected Results

  • If step #1 is false, then this failure condition applies and content fails the Success Criterion.
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