Comments on: Type 3 fonts http://www.prepressure.com Prepress, printing, PDF, PostScript, Fonts and stuff... Wed, 08 Feb 2012 21:01:19 +0000 hourly 1 http://wordpress.org/?v=3.2.1 By: Samuel Bronson http://www.prepressure.com/fonts/basics/type3#comment-67908 Samuel Bronson Fri, 03 Dec 2010 23:59:14 +0000 http://www.prepressure.com/fonts/basics/type3#comment-67908 Huh. Looks like your comment engine decided to include that ) as part of the URL ... sorry about that, I guess I must be spoiled from using StackOverflow too much... Huh. Looks like your comment engine decided to include that ) as part of the URL … sorry about that, I guess I must be spoiled from using StackOverflow too much…

]]> By: Samuel Bronson http://www.prepressure.com/fonts/basics/type3#comment-67907 Samuel Bronson Fri, 03 Dec 2010 23:57:22 +0000 http://www.prepressure.com/fonts/basics/type3#comment-67907 You say that Type 3 fonts were rarely bitmap fonts. This may have been true in general, once, but I doubt that it is true today. (Certainly there is no longer any good reason to use Type 3 if you aren't either (a) making a bitmap font or (b) doing something fancy like color or half-toning or some other fancy thing that is impractical to do in Type 1.) In particular, the only Type 3 fonts I've (knowingly) actually encountered were bitmapped fonts created from the output of METAFONT, a program (and programming language) created by Donald Knuth which he used to create the fonts to be used in his life's work, The Art of Computer Programming. These fonts are often used with the TeX typesetting system that he also wrote. (He took a decade or so off from TAOCP itself to create all of this after he saw how much worse his book looked after the publisher tried to switch from "hot lead" typesetting to computer typesetting between editions. Evidently he only expected it to take 6 months :-). A longer, but presumably more accurate, version of this story is available at http://www.tug.org/whatis.html) Anyway, due to the primitive state of computer typesetting technology at the time ("late 1970s"), the most sensible form of output for METAFONT was bitmap graphics + metrics -- there was no standard outline font format yet, or even any standard font format at all, but (I assume) most imagesetters could accept bitmap images at an appropriate resolution *somehow*. The bitmaps produced by METAFONT were, of course, device-dependent, but at least only METAFONT had to deal with that, not TeX. Then along came PostScript in 1984 (effectively 1985, as that's when the first printer came out), but (as you say) only the Type 3 format was documented at the time. This was no problem for use with TeX/METAFONT, since METAFONT only supported outputting bitmaps anyway. Of course, this did require PostScript files to be generated using bitmap fonts of at least an appropriate resolution for the highest quality possible, but that wasn't any harder than TeX had been, and anyway things mostly looked okay if you used (say) 600 dpi fonts. So mostly everyone was happy, at least until Acrobat Reader came along with it's really lousy rendering of Type 3 fonts (at least those of the bitmap variety). So, anyway, due to Acrobat's bad Type 3 rendering, we now have some quite faithful, well-hinted conversions of Knuth's original Computer Modern fonts to Type 1 (along with AMS additional math fonts), but we still have lots of papers floating around that were originally posted in PostScript files produced on systems that were not yet configured to use the Type 1 fonts (either because they were unavailable at the time, or the system had not been updated to use them yet -- and of course some TeX systems are easy to install wrong such that they still have this problem). And there *are* some other METAFONT-based fonts out there that aren't yet generally available/installed, I guess... You say that Type 3 fonts were rarely bitmap fonts. This may have been true in general, once, but I doubt that it is true today. (Certainly there is no longer any good reason to use Type 3 if you aren’t either (a) making a bitmap font or (b) doing something fancy like color or half-toning or some other fancy thing that is impractical to do in Type 1.)

In particular, the only Type 3 fonts I’ve (knowingly) actually encountered were bitmapped fonts created from the output of METAFONT, a program (and programming language) created by Donald Knuth which he used to create the fonts to be used in his life’s work, The Art of Computer Programming. These fonts are often used with the TeX typesetting system that he also wrote.

(He took a decade or so off from TAOCP itself to create all of this after he saw how much worse his book looked after the publisher tried to switch from “hot lead” typesetting to computer typesetting between editions. Evidently he only expected it to take 6 months :-) . A longer, but presumably more accurate, version of this story is available at http://www.tug.org/whatis.html)

Anyway, due to the primitive state of computer typesetting technology at the time (“late 1970s”), the most sensible form of output for METAFONT was bitmap graphics + metrics — there was no standard outline font format yet, or even any standard font format at all, but (I assume) most imagesetters could accept bitmap images at an appropriate resolution *somehow*. The bitmaps produced by METAFONT were, of course, device-dependent, but at least only METAFONT had to deal with that, not TeX.

Then along came PostScript in 1984 (effectively 1985, as that’s when the first printer came out), but (as you say) only the Type 3 format was documented at the time. This was no problem for use with TeX/METAFONT, since METAFONT only supported outputting bitmaps anyway. Of course, this did require PostScript files to be generated using bitmap fonts of at least an appropriate resolution for the highest quality possible, but that wasn’t any harder than TeX had been, and anyway things mostly looked okay if you used (say) 600 dpi fonts. So mostly everyone was happy, at least until Acrobat Reader came along with it’s really lousy rendering of Type 3 fonts (at least those of the bitmap variety).

So, anyway, due to Acrobat’s bad Type 3 rendering, we now have some quite faithful, well-hinted conversions of Knuth’s original Computer Modern fonts to Type 1 (along with AMS additional math fonts), but we still have lots of papers floating around that were originally posted in PostScript files produced on systems that were not yet configured to use the Type 1 fonts (either because they were unavailable at the time, or the system had not been updated to use them yet — and of course some TeX systems are easy to install wrong such that they still have this problem).

And there *are* some other METAFONT-based fonts out there that aren’t yet generally available/installed, I guess…

]]>