A font is a technical implementation of a typeface. The typeface is what we’ve been making so far. I used a simple vector drawing program (Inkscape), but you could use a pen and paper to sketch the glyphs too. But for an app like a word processor or web browser to use the letters we’ve drawn, the glyphs need to be digitized and packaged in a font file. Font files store the letters of the typeface in specific spots that apps know to look in to find that particular glyph. All modern font formats also include information on letter width and kerning (custom letter spacing), and some can do stuff like substitute ligatures and toggle on and off old style figures (we’ll get to those).
Before you can start putting a font together, though, you have to work out the em size. The em is the height of an imaginary rectangle than the letters of your font are mounted on. In the days of metal type, the em was an actual block of metal that had the letter on it (each metal block with its letter was called a sort). The em could be different sizes—an 8 point em would be half the size of a 16 point em, and the letter on the sort would scale with the em.
|An actual piece of metal type (the ﬁ glyph) from Garamond.|
Credit Daniel Ullrich, on Wikimedia Commons
|Text from Wikipedia|
The reason for this is because you don’t know how big the letters on the metal type are relative to the body of the metal type itself. Two pieces of type from different fonts could both have a point size of 24, but the letter on one could be bigger or smaller than the letter on the other. So point size doesn’t necessarily translate to an absolute letter size.
|Both sorts have the same point size, but the letter on the first one is half the size of the letter on the other.|
|If the letter size is the same, a smaller point sort with leading will print exactly the same as a larger point sort with no leading.|
There’s some crap out there about the golden ratio and stuff, but personally I don’t buy it, and to scale my typeface, I’m just going to do the simple thing: match it to existing fonts. I took a copy of Linux Libertine, set it at 800 points, and scaled up my typeface to roughly match its x-height.
Part two will be on ascent and descent metrics and the specifics of importing glyphs into font design software.