from the site https://www.pdfa.org/accessibility-%c2%96-what-pdfa-1a-really-means/ ..."Creating PDF/A-1a (accessible) PDFs The key thing to understand is that a really good PDF/A-1a file is one that also complies with PDF/UA. Creating accessible PDF automatically directly from an authoring application is possible, but first and foremost requires the PDF creation software to be capable of generating PDF tags. A wide variety of applications, from Adobe AcrobatÃs plugin to Microsoft Word to AdobeÃs InDesign and FrameMaker, as well as free applications such as Open Office, can create tagged PDF. However, itÃs not enough to simply use the right software and push the right buttons. Tags must correctly represent the logical structure of the document. Ensuring tags are correctly applied requires strict guidelines governing document authoring, layout and production. Styles must be appropriately named and/or role-mapped, and then employed consistently and correctly. Table structure must be well-considered and implemented; images need alternate text; heading tags should descend from H1 to H2 and H3 without skipping, and so on. Manual validation work may be minimized or eliminated through authoring practices that are sensitive to accessibility requirements. Absent careful, accessibility-oriented authoring, alternate text for images, complex layouts, tables and forms will require human validation into the foreseeable future. In principle, structured documents are just better. Teach the authors how to write documents with an eye for the concerns of accessibility and the problem is solved in the most cost-effective possible way. Never * Use color or contrast alone to indicate meaning * Use design to convey meaning in a way that canÃt be expressed though the documentÃs text Avoid * Spanning table cells, complex table structures in general * Table tags without tabular data * Illustrations comprised of many small vector graphics * Overlapping elements * Background images Always * Prefer simpler layouts * Address the need for alternate text for graphics early in the authoring process"...
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