A document that still opens decades from now, and that everybody can read

Two things are asked of a serious document nowadays. That it can still be opened and read a very long time from now, by an auditor, a public body or a court. And that somebody who cannot see the page can still be told what is on it. Both have written requirements. The engine writes all four parts of the archival family, from PDF/A-1 to PDF/A-4, and both parts of the accessibility requirements called PDF/UA, and veraPDF — a free checker that has never heard of us — accepts them.

Why an ordinary PDF may not reopen decades from now

A PDF does not have to carry everything it needs. That is not a fault in one program or another: the format allows it, which is exactly why a separate set of requirements had to be written to forbid it.

• A font that was never put into the file, and is no longer on any machine: the text is redrawn in something else, and the whole layout shifts.
• A colour described as whatever this particular screen calls red, rather than as a measurement: the document comes out a different colour.
• A picture or a font fetched from an address that no longer answers.
• A password nobody has any more, on a file nobody can open any more.
• Little programs inside the document that today's reading software refuses to run.

What an archival PDF is

There is a family of requirements written for exactly this. It is called PDF/A, and it comes in four parts, published between 2005 and 2020, each built on a later version of the PDF format. They all say the same thing: everything the document needs is inside the document, and nothing it depends on may sit outside it.

A letter after the number says how much is asked of the file. Level b promises the page will always look the same. Level u asks that the text can also be searched and copied. Level a asks for more again: the file must also say what its text is made of, so that it can be read out loud. The first part offers b and a; the second and the third offer all three; the fourth dropped the letters and has none. Ask a supplier for level a when the document has to be read out loud, and for level b when it only has to survive.

National archives ask for these by name. The United States National Archives list this whole family among the formats they prefer, the part this engine writes included. Their table of formats was last brought up to date in August 2025.

The engine writes all four parts. The first at b and a; the second and the third at b, u and a; the fourth, which rests on the current version of the format, on its own and in the form that carries files of any kind. Whichever one a supplier asks you for by name, the engine writes it.

What each of those claims asks for, and who supplies what

What an accessible PDF is, and who needs one

Somebody who cannot see the page listens to it instead. The reading software has to know what is a heading, what is a paragraph, what is a table, which cell belongs to which column, and above all in what order to say it all. A PDF that only records where the ink went says none of that, so the reading software works through the page in the order the marks were drawn — which is rarely the order a person would read them.

The requirements for this are called PDF/UA, and the engine writes both of their parts. The edition of the first in force today was published in December 2014, and the second followed in March 2024. They ask that every real piece of content be marked up and every piece of decoration be marked as decoration; that the reading order make sense; that the document state its own title and its own language; that a picture carry a description in words; and that nothing be said by colour alone.

A table that runs over two pages

A table too long for one page breaks, and starts again at the top of the next one. Its row of column headings is drawn again up there, so that somebody reading the second page still knows what is in each column.

Those requirements say nothing about that case. Nowhere do they settle what a row of headings drawn a second time is, and no word of theirs is kept for it. So the choice is ours, made in the spirit of what they do say: it is the same heading put down twice, not a second heading. A column headed March is one column, whichever page it is read on. The words stay where they are drawn, so they are still read out, selected and searched on both pages, while the structure written inside the document names that column once.

In Europe it is the law:

• A European directive of 26 October 2016 obliges public bodies to make what they publish usable. Office documents are in it: the only ones it leaves out are those published before 23 September 2018, so everything put online since that day falls under it — PDFs included.
• The European standard those requirements point at has a name and a number, EN 301 549, and it gives a whole chapter to documents that are not web pages — which means the PDF a visitor downloads.
• In France this is owed by public bodies and by companies turning over more than 250 million euros a year in France, and by nobody else: a small business owes none of it. For those it does reach, the fine can reach 50 000 euros, decided by the media regulator, Arcom, under an order of 6 September 2023, and it may be handed down again six months later if nothing has changed.
• And a further European law reaches past public bodies — into banking, transport, selling online and digital books — for anything put on the market or supplied after 28 June 2025.

Who decides whether a document really complies

Not the company that wrote it. There is a free program called veraPDF whose whole job is to open a file and check it, requirement by requirement, against the published texts. It is run by the Open Preservation Foundation and the PDF Association, two bodies whose business is keeping documents readable, and we own no part of either. It knows nothing about who wrote the file in front of it, and it answers pass or fail.

What that checker decides, how to run it yourself, and the two uses made of it here

The fine points of this standard, and what is still being checked

What our documents pass

The archival examples published on this site claim the third part at level B, and veraPDF accepts them as that. Before a change enters the library or the service, the same pages asked for over the network go back to it at that same level, and the example behind the accessible one is written again — once claiming the accessibility requirements built on the newer standard, once claiming an archival level — and handed over as well; a refusal stops the check where it stands.

• the page will still look exactly the same for as long as anybody keeps the file;
• the text inside it is written in order, so a program knows a heading from a paragraph;
• somebody who cannot see the page can have it read out to them properly.

Almost none of it is done by hand. You say the document is an archival one, and the engine sees to what that involves: the fonts go in — only the letters actually used — the colours are described, the metadata packet is written, each paragraph is marked up as it is laid out, and a table builds its own structure, headings and all. What stays with you is the outline: which part of the document is a section, and in what order it should be read.

See a document that carries its own structure See an archival form

Where to start

If you answer calls for tender from public bodies, or if you keep documents to be reopened decades from now, this is the difference between a file that is accepted and one that comes back. It costs you nothing extra: it is the same engine, and every paid offer includes it. Two of these claims alone wait on a licence key — the accessibility rules and the archival level A — because both rest on each mark on the page saying what it stands for, and a copy with no key writes its pages as traced shapes.

See the prices See the examples