Nested alternate text – Failed

Nested alternate text – Failed means the Accessibility Checker in Adobe Acrobat Pro found alt text, a description that screen readers read in place of content, in the wrong place. A tag in the document's hidden structure has alt text, and it sits inside another tag that also has alt text. Screen readers read the outer tag's alt text and skip everything inside it, so the inner description is never heard. Its sibling rule in the same Alternate Text category, Hides annotation – Failed, catches alt text on a tag that contains a link or another annotation, which hides that annotation from screen reader users.

What this means

Alt text replaces everything inside its tag. That's exactly what you want for a picture, but it causes trouble when the alt text sits on the wrong tag:

• Nested alternate text: a Figure with alt text sits inside a Sect, Div or another Figure that also has alt text. Only the outer description is read. Adobe's help puts it simply: screen readers don't read the alternate text for nested elements.
• Hides annotation: a tag with alt text contains a link, comment or other annotation. The screen reader reads the alt text and never reaches the link, so people can't use it. Adobe's help says alternate text can't hide an annotation.

Common causes:

• Alt text was typed into a container tag by mistake while working in the Tags panel.
• A whole region of a page was tagged as one figure, and then the images inside it got their own figures and alt text.
• An image that's also a link got its alt text on a tag that wraps the link.
• A group of shapes in the source had descriptions on both the group and the shapes in it.

Why it matters

With nested alt text, screen reader users miss descriptions. With hidden annotations, they can't reach links, which can mean they can't get to a form, a map or the next document they need. This affects WCAG 2.1 success criteria 1.1.1 Non-text Content and 4.1.2 Name, Role, Value.

How to fix it in Acrobat Pro

Fix it in the source file

Most nested alt text starts with how images are grouped and described in the source:

• Word and PowerPoint: when pictures or shapes are grouped, describe either the group or the pieces, not both. A diagram usually needs one description on the group, with the pieces marked as decorative.
• Linked images: add the alt text to the picture itself, and the link to the picture, rather than wrapping both in a text box with its own description.
• InDesign: give alt text to the image frame, not to a group or anchored frame that holds it.

Then export a new tagged PDF and run Acrobat's check again.

Fix it automatically with Includoc

Includoc fixes this automatically. We move or remove misplaced alt text so each description is read once, on the right tag, and we make sure no description hides a link or other annotation.

What stays with you is the wording. Every alt text in the document, including any we moved, goes to the review screen for you to approve or edit, because a machine can't tell whether a description says what an image means.

Standards

Related errors

• Associated with content – Failed: alt text on a tag that has nothing on the page.
• Figures alternate text – Failed: figures with no alt text at all.

For help writing descriptions once they're in the right place, read How to write alt text, or check a PDF free to find misplaced alt text.