When preparing a book manuscript for publication, you will have to write alt-text for any images that you are including in the book. What is alt-text? What are the do’s and don’ts when writing alt-texts?
What Is Alt-Text and Why Is It Used?
Alt-text (short for “alternative text”) is text that accompanies images, both on the internet and in digital publications (such as e-books). It’s used to make visual content accessible for people with visual disabilities or for individuals with a slow internet connection so that when an image doesn’t load, the alt-text will display instead. Search engines also use alt-text when indexing websites, so if you provide alt-text for any images on a website page, it makes the website more discoverable.
When it comes to book manuscripts, most publishers nowadays request authors to provide alt-text because it is often required by law (e.g., the European Accessibility Act) to make products accessible to a wider range of readers. Most publishers provide some guidelines on what to include in an image’s alt- text. So, if you have been asked to provide alt-text with your book’s images, you should start with the information you have been given. If you have received no guidance or want to learn more about good practices for writing alt-text for images in a book manuscript, read on.
How Do You Write Alt-Text?
Consider the Function of the Image
When writing alt-text, the first thing to keep in mind is that it needs to convey the function of the image in your manuscript. This means that your image needs to have a function and provide some essential information; it cannot be merely decorative. It also means that the same image used in different manuscripts may be accompanied by different alt-text because the image’s function may differ in each text.
Alt-text vs. Captions vs. Long Descriptions
The alt-text is not the same the figure caption; it’s also different from the long description. Captions are short, descriptive titles that accompany every image; long descriptions are for images that are complex and require a longer explanation. Long descriptions are provided in addition to the figure caption and the alt-text but only when needed. If you’re unsure whether you need to prepare a long description in addition to the figure caption and the alt-text, it’s probably best to check with the acquisition editor you are working with.
What Are the Characteristics of Well-Written Alt-Text?
When writing alt-text, you should ensure it has the following characteristics:
Targeted and Specific
✅ The image is not decorative but an essential element of the manuscript.
✅ The alt-text is written specifically for the manuscript in which the figure is used.
✅ The alt-text contains no vague language. For example, rather than writing “image,” you have identified the kind of image (e.g., photo, map, painting).
Unique
✅ The alt-text does not simply repeat the information contained in the figure caption.
✅ The alt-text does not repeat text surrounding the image.
Descriptive and Objective
✅ The alt-text is descriptive and objective.
✅ The alt-text does not include interpretations or assumptions.
Concise
✅ The alt-text consists of 1 to 2 sentences and 25 to 30 words total.
✅ The alt-text contains more than 10 words.
✅ The alt-text does not exceed 100 words. (Note: Some publishers allow for more words.)
Clear
✅ Contractions are spelled out.
✅ Numbers used are spelled out (e.g., “231” is written as “two-hundred thirty-one”).
✅ Symbols, such as mathematical symbols, are written out (e.g., “+” is written out as “plus” or “add,” depending on the context).
✅ The alt-text spells out any text that appears in the image.
✅ Non-Latin letters are spelled out.
✅ Plain text is used: The alt-text contains no bold or italicised text, superscript, bullet points, or other formatting.
✅ Acronyms that may be read as single words by assistive technology have a space inserted between each character, e.g., “U N” rather than “UN.”
Consistent
✅ If there are several images in the manuscript, the alt-text is written in the same style and language for all images and also matches the style and language of the manuscript itself.
✅ The alt-text does not contain additional information that the sighted reader does not have.
Complete
✅ The alt-text sentence or sentences end with a full-stop.
Download the Alt-Text Good Practices Checklist
Want to download this alt-text checklist? You can do so here:
Download Alt-Text CheckList (DOCX) or Download Alt-Text Checklist (PDF)
If you would like to see examples of well-written alt-text, there will be a follow-up post for that.