## Spaces, Digital and Analog

I realized recently that one of my blindnesses in typography concerned spaces. I have not been thinking critically about spaces, even though I’ve decided they are important in Stowe’s UTC. I guess it’s time to start whacking at the weeds of my own ignorance.

From Gaskell’s A New Introduction to Bibliography (pg. 45) I learn that spaces were standardized in nineteenth-century printing. An “em,” the standard length, is approximately the length of the letter m, which was a square piece of type. So spaces, and their uses, are as follows:

• thick space, three to the em, standard word spacing
• middle space, four to the em, tighter spacing
• thin space, five to the em, for very tight spacing and for punctuation marks

Gaskell does not discuss the quads, but an artisanal printer’s association has published Fred Williams’s Joy of Handsetting Type, which offers the following guidelines

• En Quad, one-half width of em quad, for spacing all cap lines
• Em Quad, paragraph indentation for short lines, but 1.5 ems for longer lines

The most advanced typesetting system, Donald Knuth’s TeX, offers fine-tuned spacing that one can use to digitally approximate metal pieces of type. See TeXbook, 166-67.

• Two Em Quad (encoded \qquad): a quad two ems in length, has width but no height
• One Em Quad (encoded \quad): a quad one em in length
• Thin Space (encoded \,): normally 1/6 of a quad
• Medium space (encoded \>): normally 2/9 of a quad
• Thick space (encoded \;): normally 5/18 of a quad
• Negative thin space (encoded \!) normally -1/6 of a quad

There are two difference between analog and TeX’s digital type. In digital, a quad has width but no height. I guess I’ll have to test to figure out whether spaces have height. The digital “Negative thin space” is not available as a concept for analog type.

I suppose I’ll need to update this post with UNICODE. But that will be for another day.