Tagged structure
A real tag tree, so a screen reader can navigate the document instead of guessing at a flat stream of text.
Thanos Core 3.5
Your PDFs, readable by everyone.
A PDF that looks fine can still be unreadable to a screen reader: no tags, no headings, no reading order. We remediate PDFs to WCAG 2.2 AA, & we prove it with the same battery we run on our own site, with a human approving every fix before it ships.
Why it matters
PDFs are part of your accessibility surface. Reports, proposals, decks, & forms all reach visitors as PDFs, & an untagged PDF shuts out every visitor who reads with a screen reader. It also puts you on the wrong side of the standard your own site claims to meet.
The fix is not a new export button. It is structure: tags, headings, tables, links, & language, checked by a battery that walks the document the way a screen reader does. That is the work, & it is the work we do.
What we fix
Structure first. Cosmetics never.
Every fix below is a structural repair, not a visual touch up. The document looks the same. It reads completely differently.
Real headings
Heading levels that match the document, promoted by matching text, never guessed or pasted on top.
Tables that read right
Header cells marked, so rows & columns make sense when heard, not just when seen.
Links that work
Every link annotation tagged in the structure, so a screen reader announces it & it goes where it says.
Language, titles & metadata
Document language, document title, & PDF/UA metadata set on every file, so tools & readers know what they hold.
Alt text, honestly written
Figures get alt text that describes what they visibly show. Data a figure does not show is never invented.
Reading order
Content in the order it should be heard, checked by traversal, not by how it looks on the page.
The battery: proof before anything ships
No PDF ships or stays published without passing the battery. Four checks, every file, every time.
- Screen reader traversal: the document walked the way a screen reader walks it, headings, paragraphs, figures, & tables in order.
- veraPDF PDF/UA-1: the international accessibility standard for PDFs, checked rule by rule.
- Strict 4.5:1 contrast: every text & background pair, with no large text exception.
- String presence proof: every expected string confirmed present & tagged, so nothing is silently dropped.
Proven on our own site first
We ran this on ourselves first. In October 2026 we remediated all 4 PDFs on thanoslab.com & re-verified them: tagged structure trees, language set, document titles, real heading levels, table header cells, & clean reading order.
Across our WCAG program we battery tested & remediated 54 PDFs: 27 fixed, 9 passed as they were, 12 need a rebuild from source, & 6 still failing, as of October 14, 2026. Those numbers are the record, including the files we could not fix in place.
What we never do
- Never invent alt text. If a figure has no honest description, we say so. We do not fabricate data.
- Never hide a limitation. The known LibreOffice decorative vector limitation is documented on the report, never buried.
- Never ship without the battery passing. A PDF that fails stays unpublished until it is fixed or rebuilt.
- Never publish without human approval. Every fix waits for a human before it reaches your visitors.
PDFs are part of the accessibility surface. The same care your pages get, your documents get too.
Thanos for Accessibility audits WCAG 2.2 AA barriers, proposes fixes, & retests after approval. See how your site scores today, & where your documents sit in the picture.
Get your free audit.
Tell us about your PDFs. We will review them properly & email your audit once it is ready.
Get your free auditFrequently asked questions
Straight answers about how PDF remediation works & what it can & cannot fix.
The PDF gets a tagged structure tree, real headings, marked table headers, tagged links, language & title set, & alt text for its figures, then it must pass the battery: screen reader traversal, veraPDF PDF/UA-1, strict 4.5:1 contrast, & string presence proof. A file that fails stays unpublished until it is fixed or rebuilt.
No. Some PDFs are untagged at source with no structure tree to repair, & those need a rebuild from the source file. We say so plainly & give the verdict, never a silent rewrite. Our verdicts are fixed, passed as it was, still failing, needs a rebuild, or needs your call.
We write alt text that faithfully describes what the figure visibly shows. If it cannot honestly be described, we flag it for your call instead of inventing data. Invented alt text is fabrication, & we do not do it.
Every file ships with its battery results: the traversal, the veraPDF PDF/UA-1 result, the contrast check, & the string presence proof. The evidence travels with the file, & any known limitation is documented on the report, never buried.
It depends on the file. A short tagged report moves faster than a long untagged deck, & a file that needs a rebuild takes longer than one that can be repaired in place. Ask for a review & we will tell you before any work starts.
PDF remediation is billable work, & there is no standard price listed here. Tell us about your files & we will quote before any work starts.