veraPDF
veraPDF is a free program that opens a document and says whether it really follows the rule it claims to follow.
What the word means
A file can say anything about itself. A line inside it may claim it follows the archival rule. That claim costs nothing to write and proves nothing.
veraPDF reads the whole file and checks the claim against the published rule, point by point. It comes back with a plain yes, or with the list of what is wrong and where. Nobody has to take the maker's word for it, which is the entire point.
What it does on a real document
Every archival document shown on this site is put through veraPDF before it is published. The document is written, then handed to the checker, and only a file that comes back clean is kept.
When it refuses, it names the rule it is refusing under. A typeface that is in the file but missing a piece of its identity card, a colour with nothing saying what it should look like, a picture with no description: each is a separate line of the report, with the exact part of the document it concerns.
Where it comes from, and why
It was built in the middle of the 2010s by a group led by the Open Preservation Foundation and the PDF Association, paid for by a European Union programme called PREFORMA. The aim of that programme was to give libraries, archives and museums checking tools they own rather than rent.
That is why it is free and why anybody may read how it works. An archive that has to open a file in forty years cannot depend on a company still selling a program in forty years. It has since learned to check accessible documents as well as archival ones.
See it on a finished document
An archivable PDF/A-3 form The rules behind this word, and the texts they are read from