A very interesting article by Eildert Mulder about the difficulty of setting Arabic script in type:
The technical problem is this: Arabic letters are generally not written separately but joined to each other in groups or entire words, like a script typeface in English. And though the Arabic alphabet has only 28 letters, most letters have four forms, depending on whether they occur at the beginning of the word, in the middle of the word, at the end of the word, or stand alone. Furthermore, each combination of letters is unique, creating a typographic challenge greater than Chinese. Because all letters connect dynamically with the preceding one, and most also with the following one, the number of unique combinations is almost astronomical.
The esthetic problem comes from the dizzying mutability of written Arabic. For example, there are actually three ways the letter ha can be written in the middle of a word, and the calligrapher’s choice is influenced not only by the letter immediately preceding the ha, but also by the letters earlier in the word, and even by letters that follow it—yet, in whatever form, it is still in essence the ha in the beginner’s textbook. A sequence of letters can run along a baseline the way Roman letters do—though Arabic runs from right to left, of course—or they may start above the baseline and descend in a diagonal if the connections from one letter to the next make that an esthetically pleasing choice.
The result is that the individual letters in a well-written piece of text are in constant motion, like dancers in a polonaise: In the course of the dance, they bow to each other, embrace each other, push each other away, hug each other’s necks and fall at each other’s feet—and there are some real acrobats among them. Thus, well-written Arabic texts feel alive to their readers, whereas mechanically typeset ones feel like graveyards: At their best they are only still photographs of the calligrapher’s living, moving polonaise.
Thomas Milo, Mirjam Somers, and Peter Somers have solved this problem:
Using the calligraphy of Mustafa Izzet Effendi and other great calligraphers, the Milo–Somers team took the concept of script analysis further than either Müteferrika or Mühendisyan, making the basic unit they examined not the letter but the penstroke. That made it possible to derive the dancing, shifting letters, the tens of thousands of combinations, and the variable words all from a few hundred individual penstrokes and a clear and limited set of rules—just the sort of fundamental, tabular information that computers like to use. And with modern computers, it became possible finally to resolve the conflict that has blighted the relationship between Arabic script and book-printing technology for most of five centuries.
Fascinating stuff, with some gorgeous illustrations. (Via MetaFilter.)