What is "Point Size"?

In general terms, point size is a relative measure of the size of a font. It used to have a more concrete meaning in the "old days" of typography. (See Difference between point systems for more information on the origin of the point unit).

Nowadays in the world of electronic imagesetters and digital fonts, the distance from the top of the tallest ascender to the bottom of the longest descender is only an approximate lower bound on the point size of a font. However in the past, it was almost always a firm lower bound.

Point size is the measure of default or minimum inter-baseline distance; inter line distance in absence of leading, AKA "set solid". If you don't know if the text was set solid or leaded, you can't tell the point size with a measuring glass unless you know if the type design includes built-in space between adjacent, set-solid lines.

In metal, there was usually a little room between the highest and lowest corners of the face and the body size, so that the matrix was completely molding the face and not relying on the mold-body to form a vertical side to the printing face - since a bevel or beard is desirable for impression and strength.

If the designer of a face thinks it should always be set leaded (with extra interline spacing), he or she may choose to include the minimal leading in the design, in which case it is included in the base point size, and no capital, lowercase-ascender, or lowercase-descender will get very near the edges. In this case, a font with the same point size will look smaller than non-leaded font.

Here is an example of fonts looking different at the same point size. You can see that Arial looks larger than the same size Bernhard Fashion BT:

So, unless you know it's Adobe Times Roman or whatever and just want to know what point size & leading options were, you can't measure the size with a definition and an optical micrometer.

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Copyright 2000 by Alex Vakulenko. All rights reserved.
This page was last revised on 02/20/00.