The oldest font format, and one box we had to tick

Why a file has to carry its own lettering

A font is a file full of drawings: one drawing per letter, per figure, per punctuation mark. Your computer holds a few hundred of them, and so does everybody else's — but not the same few hundred.

So a document that merely names the lettering it wants is a document at the mercy of the machine it is opened on. If that machine has never heard of the font, it puts something else in its place, the lines come out a different length, and the page you approved is not the page your customer reads.

The way out is to put the drawings inside the document. That is what this engine does: the lettering travels with the file, and the file looks the same in twenty years, on a machine nobody has bought yet.

The little identity card beside each font

Next to the drawings, a PDF writes a few lines about the font: the name it goes by, how tall its letters climb and how far they drop below the line, whether they lean over, how thick a downstroke is. Think of it as an identity card. It is short, and every line of it is supposed to be true.

One line of that card is a set of boxes to tick. Two of those boxes matter here, and only one of the two may be ticked: this font writes ordinary words, or this font writes a set of signs — arrows, ornaments, mathematics, the sort of thing that is not an alphabet.

What that box is actually for — and what it is not for

Here is the part that surprises people: that box changes nothing about what you see on the page. Not the shape of a letter, not the spacing, not the colour, not one dot of ink.

It is read in one situation only: when the font is missing and the program has to invent a stand-in. Knowing whether it is standing in for an alphabet or for a set of arrows helps it invent a less embarrassing one.

And that situation cannot arise in a file this engine writes, because the font is inside the file. The box is therefore true or false the way a form is filled in correctly or carelessly — it costs nothing today, and it is the sort of thing a checker looks at.

Why the question comes up for these old fonts in particular

Adobe's first font format dates from 1990. It is still the format a print shop's older library is held in, which is why the engine reads it at all: a customer with three hundred faces bought over twenty years should not have to throw them away.

A font in that format carries its own little table saying which number reaches which drawing — number 65 is the capital A, number 233 is the e with an accent, and so on. Some of these fonts carry a table of their own making. Others say, in effect, use the published table everybody already knows.

Nothing in the published rules says which box to tick for either case. The rules say what the box means; they do not say who decides it. So somebody has to decide, and that somebody was us.

The rule we chose

A font that brings a table of its own is written down as a font of signs. A font that points at the published table is written down as a font of ordinary words.

The reasoning is plain. Bringing your own table is exactly what a font does when it does not fit the ordinary alphabet — when number 65 is not a capital A but an arrow, an ornament or a company logo. Pointing at the published table is exactly what a font does when it is an ordinary alphabet. The rule follows the only clue the font itself gives us, instead of guessing from its name.

We could have ticked the same box every time and moved on. We did not, because a card that says the same thing about every font is a card that says nothing about any of them.

What we checked before choosing it

There is a standard for documents meant to be readable in twenty years, and a free checker that says yes or no against it. That checker carries every rule it applies, in writing, in a form we can read.

We read them before deciding. Exactly one rule ties this box to anything else: a font of signs must not also carry a table of its own. It sounded like it might bite — until we read the small print, which limits that rule to a different font format altogether. For the fonts on this page, neither answer breaks anything.

Then we checked the other way round: a document carrying one of these old fonts was put through the checker, and it passes. Not because we say so — because the checker says so, and it knows nothing about what wrote the file.

What it changes for you

On the page you print: nothing at all. On the file: one line of the identity card is filled in from what the font actually says about itself, rather than from a habit or a guess.

We are writing it here for the same reason we write down every figure our examples state: a decision you cannot see is a decision you cannot check. If you would rather we ticked the box differently for your files, that is a conversation, not a rewrite.

One more thing these fonts do differently

With every other kind of font, the engine travels light: only the letters your page actually draws go into the file. Write one word, carry one word's worth of drawings.

A font in this old format travels whole. The reason is in the format: every drawing inside it is scrambled separately, so keeping some and dropping the rest means unscrambling the whole thing, rewriting its list of drawings and scrambling it again — while holding on to the strokes that several letters share, and to the letters built out of two others.

That is a piece of work of its own, and we have deliberately left it for a later version. It costs nothing on a small face. On a large one it costs real bytes: a font of sixty thousand bytes travels sixty thousand bytes even where the page shows three words. We would rather tell you that plainly than have you find it out from a file that is bigger than you expected.

See it on a finished document

A page set in one of these fonts, stating what the font says about itself What makes a file readable in twenty years

See the prices See the examples