OFFTOPIC: Font Metrics and Typographic Units

From: Mirko Raner (
Date: Wed Jan 13 1999 - 13:50:55 EST

Hello Unicoders,

my question is a little bit off topic but I know that also many typography
experts, font designers and ISO members are paying attention to this list.

I would like to know whether there are any standards or maybe ISO
recommendations about typographic units (eg, point, pica, ...).
The special problem is that there are two different definitions of the
unit "point". The PostScript standard treats 1 point as 1/72th of an inch.
In conjunction with digital typesetting systems such as TeX 1 point is
defined to be 1/72.27th of an inch. Another problem might be that there
are also different definitions of an inch, in most cases 1 inch is
defined as 2.54000... cm (I heard some people calling this a "technical inch"),
however this seems to be just some handy rounding; the "original" inch seems
to be somewhat longer than 2.54 cm (I don't know the exact number).

My question now is: is there an ISO statement (or maybe a statement of some
other organization, maybe the AFII?) about which units of
measurement should be used in digital typography and which distances they
exactly represent? (I know that according to the SI the meter (m) and its
sub-units should be used for measuring lengths and distances - but that is
not what I would like to hear...)

Please answer directly to and do not reply to as this topic is not really Unicode-related.



Mirko Raner
Software Developer
MATHEMA Software GmbH

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