PDF/A is a subset of PDF defined by ISO standard 19005. The 'A' stands for archival. A PDF/A file is self-contained: all fonts are embedded inside the file, all colour profiles are included, and the file does not reference any external resources. Open a PDF/A file in ten years on a machine that has never seen the original fonts or software, and it will render exactly the same.
Regular PDFs can contain references to external fonts, scripts that execute when the file opens, and links to external content. Those dependencies can break over time. PDF/A eliminates them at the point of creation.
When PDF/A is required
Courts, government agencies, and regulated industries often require PDF/A for formal submissions. If you are filing a document with a public registry, submitting to a court, or depositing files with a national archive, the specification will likely say 'PDF/A-1b' or 'PDF/A-2b.'
Document management systems that need to guarantee future readability also require PDF/A. Long-term storage in sectors like healthcare, finance, and law means files need to be readable for decades, not just until the software that created them is updated.
PDF/A-1b vs PDF/A-2b
PDF/A-1b (ISO 19005-1, 2005) is the original standard. It is the most widely supported and required by the oldest compliance systems. Limitations: no transparency, no JPEG 2000, no embedded files.
PDF/A-2b (ISO 19005-2, 2011) is a more modern revision. It supports transparency, JPEG 2000 compression, embedded PDF/A files, and digital signatures. It is accepted by virtually all systems that accept PDF/A-1b and is a better choice for documents created in the last decade.
Filum converts to PDF/A-2b. If a specific system requires PDF/A-1b, check with the receiving system — most accept PDF/A-2b.
What the conversion actually does
Converting to PDF/A is not simply adding metadata. LibreOffice opens the PDF and re-renders it, embedding all fonts, attaching an ICC colour profile, writing the required XMP metadata block, and removing any non-conforming elements (scripts, external links, transparency layers that cannot be flattened).
For PDFs that were originally created from office software — Word, Excel, LibreOffice, or most accounting and legal software — this process is transparent: the output looks identical to the input. For PDFs with unusual custom fonts, heavily layered vector graphics, or embedded JavaScript, the output may have minor visual differences.
File handling
PDF to PDF/A uses LibreOffice running on a secure server. Your file is sent over an encrypted connection, converted, and deleted immediately — it is never stored. The tool does not offer on-device conversion because embedding colour profiles and validating compliance requires a full document rendering engine that cannot run in a browser at the quality required.