Why can’t we directly measure the point size of a printed font?
Em sizing.
Some typography concepts have evolved in response to changes in technology. For instance, in the digital age, a carriage return gets inserted at the end of a paragraph, whereas on a typewriter it was used at the end of a line. And today, the word
But other concepts have been surprisingly durable, like the em. In hyphens and dashes, I mentioned that the word
It’s remained true in the digital era. Today, the em is implemented in software rather than metal. But it still represents the same thing: the maximum vertical size of the letters in the font. Then and now, two fonts set at the same point size will appear to be different sizes if one occupies less space on its em.
Instead, by relying on maximum size, the em-sizing system can be applied to any font. This ends up being a useful convention for automated typesetting. But as you learned in the previous section, it’s also why you can’t determine the point size of a font by measuring it directly.
If you think that’s merely nerdy trivia, you’d be wrong. A 2012 case in the Michigan Supreme Court turned largely on the meaning of point size. Michigan state law requires certain ballot measures to be
As a typographer, it was clear that this case should’ve been resolved swiftly. Point size has had a consistent meaning for hundreds of years. It’s never had anything to do with the size of capital letters.
Moreover, as a lawyer, it was clear that if this fact weren’t automatically clear from the plain meaning, it could’ve been established by citation to authority (this book is just one of many options), expert testimony, or even good old judicial notice. What was left to argue about?
A lot, apparently. The appeals court ruled that
Why alarming? None of the justices seemed alert to the potential consequences of Michigan’s highest court redefining point size as a matter of law. Had it done so, point size would have meant something different in Michigan than it does elsewhere. It would have been like the court saying