Re: Font size

Subject: Re: Font size
From: Dick Margulis <margulis -at- fiam -dot- net>
To: Bruce Byfield <bbyfield -at- axionet -dot- com>
Date: Mon, 04 Sep 2000 18:45:53 -0400

Bruce Byfield wrote:

> An important point to remember is that point size is the amount
> of space given to characters, including the white space around
> them. The actual letter form may be much smaller than the point
> size.


You're sort of right and sort of wrong. Let me explain. The point size
runs from the top of the highest character (uppercase letter, ascender
on lowercase letter, or accent/punctuation mark, as the case may be) in
the font to the bottom of the lowest (usually a descender, sometimes a
diacritical mark of some sort). As most characters do not fill all of
this height, there is clear white space above or below most characters,
and this is indeed included in the point size.

However, the additional white space that is added between lines--white
space that is an empty rectangle, with nothing extending into it from
the top or bottom--is leading. It is not part of the font. (I know you
know that, Bruce; I'm just trying to be thorough here.)

That's why the characters of two fonts of the same size can
> be different.

Not really. The reason is that different fonts have different x heights.
The x height is the height of the lowercase letter x. Some fonts have a
much larger x height (and consequently shorter ascenders and/or
descenders) than other fonts of the same point size. This gives them the
appearance of being equivalent to larger point sizes of the other fonts.
The practical effect is that legibility increases greatly while the
number of words per square inch declines only slightly. Therefore,
applications where the cost of paper is a major
consideration--newspapers, drugstore paperbacks, textbooks--generally
use large-x-height fonts.

This was the impetus behind Stanley Morison's 1931 design for the Times
(London). He called it Times New Roman. Perhaps you've heard of it <g>.
Following Morison, the major foundries started introducing a great many
"New" faces, such as New Baskerville, for example. All were built on the
same plan. That is, they followed the idiosyncratic design details of
the base font, but they shortened the ascenders and/or descenders
relative to the x-height.

Some typographers have even suggested that point
> size isn't a very good description of font size.

I'd agree that it isn't a very good description. Without saying what the
typeface is, it is pretty much useless. But it is one unambiguous datum
used in communicating between typographers and compositors. If you tell
the printer you want 10/12 ITC New Baskerville, you will not get 11/12
Baskerville or 9/12 Times New Roman. You will get 10/12 ITC New
Baskerville. You can look at a specimen and the compositor can look at a
specimen and you will both be looking at the same font. There are a lot
of other things you need to communicate to the compositor that are more
ambiguous (how tight is tight, for example); but point size, while it
may not say much about optical size, at least is a clear specification.

> I believe that this difference dates from the days of lead type.
> In those days, a letter couldn't go the edge of its block without
> the risk of the block cracking in the press.

Sort of. Beyond the actual limit of the visible portion of a
character--in metal type--there is a hair of additional space, well
under a point--taken up by the shoulder. The shoulder is the metal below
the type's top surface that slopes down toward the body that the
character sits on. This is an artifact of molding technology and, as you
suggest, makes the type stronger. The shoulder of the tallest character
ends exactly at the limit of the body.

This is quite different from the side bearings, which are clear areas
between the left and right edges of a character and the edges of the
body. The side bearings are design features carefully sized by the type
designer to equalize the apparent amount of space between pairs of
characters. (What I'm saying is that designers did not include top and
bottom bearings. They assumed the typographer would specify an amount of
leading instead.

Here is where electronic type revolutionized font design. The designer
of metal type did the best he (only rarely she) could, but pairs like
Ta, WA, Ly, etc., had awkwardly large spaces. In display typography
(advertising headlines, book jackets, chapter titles, ...) careful
compositors carried the individual sorts (letters of foundry type) over
to a miniature table saw called a kerning saw and sliced a wedge off the
bodies of the adjacent characters in these pairs, so that the character
itself was supported by the body of the adjacent character. Nowadays,
fonts include tables of kerning pairs and the adjustment is done
automatically. Then the compositor can tweak by clicking a button in a
typsetting application.

Oh, by the way, we all talk about lead type, but lead is too soft a
metal to use for type. Type metal is actually one of three alloys of
lead, tin, and antimony. The proportions are different for foundry type
than they are for Monotype or for Linotype, with the last having the
largest proportion of lead. Scrap dealers used to be quite shrewed in
assaying the differences based on filing a nick into a sort and
observing the color. The differences in price were significant.

On the other hand, the lead strips used for leading were made of lead
(unless they were cast on a Linotype, of course).

And all of this explains why the first paragraph after a heading is not
called a lead paragraph but is called a lede paragraph instead.



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