To be able to access and understand the content of graphics, photos, or similar visual elements (such as screenshots, shapes, or pictograms), persons using screenreader softwares need an “alternative (alt) text”. Writing a good alternative text should not be a daunting task. As we aim for inclusivity and accessibility, it is crucial to know how to write an alternative text for pictures or graphic elements that we add to our publications, articles, presentations, social media posts, etc.
It is important to think first about the reason for inserting pictures and similar visual elements in our work, what purpose they have and what we want to achieve. Is it to simply make the page more attractive for a seeing reader (such as colourful shapes or decorative, creative drawings)? Or does it transport a message (such as logos, graphs, symbols, or photos from a conference)?. Thinking about this will ensure that we write an accurate alt text. The alternative text is not the sub-title that contains a copyright or other explanation on the photo for everyone. It comes in addition and specifically addresses screen-reader users. It can be added through accessibility checkers of standard programs such as Microsoft Word or PowerPoint. Contextual information that is also not clear for the seeing reader (e.g., such that is often displayed in sub-titles) is not part of an alternative text. That said, here are some quick tips to keep in mind when writing a good alt text:
- When writing the alternative text, watch out for punctuation. Make sure to use punctuation correctly and where necessary. This way the screen reader can make sense of the sentences. Always end your alt text with a full stop.
2. Keep the alternative text short. Describe briefly what the picture is representing. You do not need to describe every detail of the picture – unless the information is relevant, as it transports content that will otherwise be unclear to the non-seeing reader. It is ok to keep the alt text to one or two sentences. Less is often more. If it is a complex chart or diagram, summarize the important elements rather than describing everything.
3. Avoid duplicating sentences that are already found in the document next to the visual element you want to describe. When it comes to pictures, there is no need to say „picture of…“ or „photo of…“. Instead, simply describe what message the picture is conveying. You can however write „logo of…“ when describing logos.
4. If you have the opportunity, you could also ask a colleague with a visual disability whether they would mind checking what you have written.
5. When inserting pictures or visual elements for decorative purposes, mark them as decorative.
Source:
For me details and examples of writing a good and helpful alt text, please refer to the Harvard University‘s Resource on Digital Accessibility.
