Many free Latin fonts are available in TeX distributions, but for most of my texts I use Latin Modern, a Computer Modern derivative with better support for most European languages. The aim of this post is to describe my main reasons for this choice.
A one of the advantages of Computer Modern results clearly from its origin. TeX, MetaFont and Computer Modern were written for one task – typesetting The Art of Computer Programming by Donald E. Knuth, although they are useful for many other texts. Originally TAOCP was typeset with Monotype Modern metal fonts. Then modern typefaces were used for nearly everything, but now they are used mostly for academic texts. So using a typeface in the modern style makes a text look more academic.
Another advantage is support for high-quality typesetting of most mathematical notations. This is a clear consequence of the original task, analysis of algorithms requires complex (in non-mathematical meaning of this word) mathematics, while non-TeX software had problems with mathematical typography (thirty years later it still has).
Computer Modern is the most well-known meta-font. It has a parametric description which is used with certain values of 62 parameters to define nearly hundred fonts. There are no other fonts for which adding a complete different style (e.g. slab serif Computer Concrete Roman) is easy. Usually amount of work is directly proportional to the number of fonts. With meta-fonts it is simple and allows things which were impossible before (nicely illustrated in a paper written by Donald Knuth, ‘The Concept of a Meta-font’ available in his book Digital Typography). Except Lucida, Palatino and Bitstream Vera, I haven’t seen a font family containing nicely matched serif and sans-serif fonts which is not a meta-font.
A nice example of advantages of meta-fonts is the support for optical scaling in Computer Modern. There are different designs for different font sizes (in Computer Modern Roman 5, 6, 7, 8, 9, 10, 12 and 17 points). It would require about eight times more work for a non-parametric font, so it was done only when necessary, i.e. when the fonts were made from lead. Therefore other fonts use affine scaling to support different type sizes, which makes too small text too light and too narrow to be nicely read.
Since Computer Modern is the default typeface in TeX, several derivative meta-fonts have been made for languages different than English. They use the same (or very similar) files with parameter values, so e.g. adding Concrete Roman support for them is trivial.
Later, when PostScript Type 1 font format became popular, outline fonts became popular. It is mathematically difficult to make an outline meta-font, so the most popular way of converting fonts like Computer Modern to this format was determining outlines of bitmaps generated from the fonts. In this way outline variants of all canonical Computer Modern fonts were made and on them Latin Modern fonts are based. They still have all advantages of the specific designs available, but making new ones is not as simple as for meta-fonts.
