Type 3 fonts

Type 3 fonts are PostScript fonts which means they are outline fonts, offering excellent output quality at every character size. Most of the information you can find in the Type 1 page also applies to PostScript Type 3 fonts. Below you find an overview of the differences between both technologies.

  • Unlike Type 1, Type 3 fonts do not support hinting, the technology that optimises character shapes at small type sizes. This means that PostScript type 1 offers slightly superior output on lower resolution devices such as laserprinters or monitors.
  • Within Type 3 fonts, the entire PostScript language can be used to describe character shapes. This means that Type 3 fonts can have more elaborate designs than Type 1 fonts: the glyphs can contain shades of gray, graduated fills or variable stroke widths. This makes it an interesting technology for fonts containing company logos or other drawings. Since even the PostScript “image” operator can be used, Type 3 fonts can also contain bitmaps (although they usually only contain vector data). The flexibility of the Type 3 technology made it a popular format for various font creation tools. It is easier to create a Type 3 font by hand than it is to do the same using PostScript Type 1 technology. I can even remember using small utilities that could embed an Illustrator EPS in a Type 3 font.
  • Type 3 fonts take up more memory than Type 1 fonts. Since Type 3 fonts are not compressed and are based on the PostScript language, one way of identifying a Type 3 font is opening the font’s outline file in a text editor and searching for the first occurrence of ‘FontType’. If the font type is ‘3 def,’ the font is a Type 3 font.
  • Since they can contain PostScript data, Type 3 fonts cannot be used with Adobe Type Manager which is not a full PostScript language interpreter.
  • Characters from a Type 3 font can look slightly bolder than they would if they were part of a Type 1 font.

At the beginning of the PostScript revolution, Adobe published the specs of the Type 3 font technology but kept the Type 1 technology to itself. This forced all font foundries to release their fonts as Type 3 fonts and for a couple of years Type 3 fonts were pretty popular. When Adobe was forced to release the specs of Type 1, all foundries moved to this standard. Nowadays OpenType is the dominant font format and Type 3 fonts hardly seem to be used anymore.

Type 3 fonts on Macintosh running System 9 or earlier

No specific PostScript Type 3 information available. Check the page on Type 1 fonts.

Type 3 fonts on Macintosh running Mac OS X

OS X still offers support for Type 3 fonts.

Type 3 fonts on Windows

Some PostScript printer drivers for Windows offer the option of downloading outline fonts as bitmap fonts and subsequently use the PostScript Type 3 font technology for this.

Type 3 fonts can be recognized by the file extension .PFA (Printer Font Ascii).

Windows XP does not support PostScript Tpe 3 fonts.

Cross platform issues

No specific PostScript Type 3 information available. Check the page on Type 1 fonts.

Outputting Type 3 fonts

I have occasionally stumbled across compatibility issues with Type 3 fonts. At some point in time, Adobe even admitted that recent versions of its RIPs may be incompatible with some very old Type 3 fonts. Fortunately Type 3 fonts are hardly used any more so I would not worry too much about them.

8 August 2013

2 responses to “Type 3 fonts”

  1. Samuel Bronson says:

    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…

  2. Samuel Bronson says:

    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…