Check the following to confirm the quality of short description text (alt text).
References/Prerequisites
Alt text is meant to be read aloud by technology and should be written with this in mind. For intricate images (charts, graphs, mathematical equations), detailed descriptions may be conveyed best in the body of the book while the alt text remains as short as possible. Determine preferences and expectations before creating and reviewing alt text.
Accuracy of Text
Length
This may be a soft limit, with certain descriptions requiring longer descriptions.
Read-Aloud Technology
https://ttsreader.com/
Microsoft Word
Characters
Alt text cannot contain these characters or any formatting, such as italics, bold, small caps, superscript, or subscript.
En dashes and em dashes need to be replaced with words or deleted, and they should not be used to separate phrases.
Example: “1920-1930” needs to be “1920 to 1930.”
Common symbols like º or % are acceptable.
Uncommon symbols may need to be spelled out. (Confirm using read-aloud technology.)
Examples: slashes, colons, ellipses, and parentheses.
Acronyms
Avoid acronyms when possible.
Acronyms need to be tested and may be read differently based on surrounding text and whether the acronym uses periods.
Example: “VFAs” reads as “vee ef aes,” but “V.F.A.s” reads as “vee ef a ess.”
Units of Measurement
Example: “km” should be spelled out as “kilometers.”
Example: Prime and double prime characters should be spelled out as “feet” and “inches,” respectively.
Numbers
Numbers may need to be spelled out as words in certain scenarios.
Example: 25000 may be read as “twenty-five thousand“ even if the intention is for the text to be read as “two five zero zero zero.“
Math and Science
Because superscripts and subscripts are prohibited, chemical names should be spelled out. (Confirm using read-aloud technology.)
If a mathemetical symbol or equation needs to be described, terms should be spelled out. (Confirm using read-aloud technology.)