LEMDO: Write Alternate Text for Images

Write Alternate Text for Images

Alternate (alt) text is text that describes the content of an image. Alt text is helpful if a user cannot see an image (e.g., the user uses a screen reader¹ or the image does not load).

Prior Reading

Embed and Style Images

Disambiguation

Alt text is different from the image caption that editors may choose to write in the


                                          <figDesc>

element because alt text gives a literal description of what is in the image. An image caption, on the other hand, may be used to provide an image’s metadata or to discuss what is depicted in the image. Alt text tends to give a more detailed description and does not supply information not visible in the image. For information on how to encode image captions with the


                                          <figDesc>

element and on how to encode alt text with the


                                          <desc>

element, go to Practice: Encode Alt Text and Image Captions.

Rationale

LEMDO adds alt text to improve website accessibility. Including alt text gives people who use screen readers access to content that would otherwise be inaccessible. This documentation will guide you through LEMDO’s principles and practice for writing alt text.

Principles

When writing alt text, LEMDO follows principles of accessibility, honesty, and clarity. Consider the following questions when you write alt text:

Does my alt text communicate the key components of this image?

Is there anything significant that a viewer of this image would see that a reader would not get out of my alt text?

Does my alt text truthfully describe what is in the image?

Does my alt text include subjective terms (e.g., describing someone as pretty or happy), or objective ones (e.g., descibing characteristics such as using a wheelchair or smiling)? Replace subjective terms with objective ones.

Is my alt text concise?

Practice: Write Alt Text

Follow these steps to write alt text for the LEMDO project:

Capture important elements of the image: Because alt text is meant to describe an image to someone who cannot view it, alt text should capture aspects that are important to the overall meaning of the image for the argument. For LEMDO, this typically includes the medium (a photograph, a wood engraving, etc.), the main subject of the image, important imagery, and background.

Include the race of all human main subjects: LEMDO has decided to include the race of people who are the subject of images, as race will be a point of discussion in many editions. In practice, capitalize the first letter of Indigenous and Black; do not capitalize white. Use the most accurate term for a person’s race or ethnicity that you can (e.g., if you know that an actor in an image is Piikani, describe them as Piikani rather than the more generic Indigenous). When describing a living or historical person rather than a character, search to see if there is information available about how they identify or identified to use the most accurate and respectful language.

Use objective language: Alt text has the goal of describing what is literally in an image, not the interpretation of a viewer or describer. To fulfill that goal, use objective language (describing what you see) rather than subjective language (describing how the image makes you feel or how you interpret it). For example, do say A photo of smiling children rather than A photo of happy children.

Use concise language: Although there are typically no restrictions in the number of characters that modern screen readers will read, some programs do not continuously read long strings of alt text. Even with new technology, best practice is to have relatively short and concise descriptions. If possible, keep descriptions under 125 characters.

Do not use quotation marks: Quotation marks in alt text can cause processing issues. If quoting text included in an image, write Text reads: or a similar descriptive phrase followed by a transcription of the text.

Transcribe relevant sections of text: If there is text in the image (e.g., a title or an artist’s signature), transcribe any section that may be relevant or that will be discussed. If there are glyphs or ligatures (e.g., a long S), normalize the characters. If the image includes old-spelling text, modernize it in your transcription to make the screen readers’ output more clear. In cases where you have modernized spelling, note that in the preferatory clause (i.e., Modernized version of text reads:). Note that alt text for images containing text will typically be necessarily long.

Special case: If an image with text is included for the purpose of demonstrating or discussing early modern spelling conventions, provide a semi-diplomatic transcription. Normalize glyphs and ligatures without tagging them, but retain spelling as it appears in the image. You may also provide a modernized transcription afterwards for clarity—not all words will be read clearly by screen readers if spelled using early modern spelling conventions.