What's the point? [was RE: Manual scanning: TIFF-to-PDF software with greyscale support?]
tshoppa at wmata.com
Mon Feb 15 13:41:51 CST 2010
> Tim wrote:
>> PDF's are fundamentally a VECTOR format. A vector format designed around
>> typography where the most natural unit since long before computers has been
>> the point (=1/72 inch).
> Technically, 100/7227 inch, which is to say, there are 72.27 points per inch
> in typography prior to the creation of the Macintosh. (I don't believe that
> Postscript originally used a 1/72 measure, and TeX certainly didn't, so I can't
> just say "non-computerized typography".)
I'm pretty sure when I learned typography the numbers I was taught was that Cicero
was 6 lines to the inch, and that it was a 12 point font. Maybe neither of those numbers
are actually correct. That was all before I had used computers although I think it's
possible that Postscript was a glimmer in someone's eye by that point.
I briefly used an IBM Composer and I'm pretty sure that defined a point = 1/72 inch before
postscript ever did, although it seems likely that it didn't originate the 1/72 measure
Most computer line printers were six lines to the inch, 66 lines to 11 inch page. This
was set by geartrain if nothing else :-). I think the Model 33 is the same.
> If you think *this* mailing list goes off-topic from time to time, you should
> check out the Letpress mailing list, for metal type and ink folks.
Knuth's Metafont book closely brought together for me, for the first time, computers
and typography, and they've been closely linked for me ever since. I could've sword
that I read that a point = 1/72 inch in there but despite some desparate scouring
he uses "point" as base unit with absolutely no attempt to map it into inches.
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