T'S one of the most frustrating problems encountered when passing documents back and forth electronically: the little square boxes that mean a font someone else used to create the file cannot be rendered on your computer. While Portable Document Format, or PDF, files, which essentially are copies of printed pages, have helped mitigate the problem for most computer users, that solution has not satisfied scientists and mathematicians, whose formulas and equations contain many symbols.

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Using those symbols on the Web has been particularly inconvenient. Most publishers use the symbol-friendly PDF format, but then researchers cannot easily embed links to other files or background information within those documents as they can with HTML files. But HTML documents have their own drawbacks. For instance, they often display equations as separate graphic images that cannot be resized or searched and greatly increase the size of the file.

Now a new set of fonts being developed by six publishers of scientific, technical and medical journals promises to contain every character - more than 7,000 in all - that might be needed in a technical article published in any scientific discipline. When complete, sometime next fall, the fonts will be shared freely with publishers, software manufacturers and scholars, under the condition that they not be altered.

"This work is a breakthrough for publishers and scientists," said Tim Ingoldsby, director of business development at the American Institute of Physics, one of the publishers working on the project, called the Scientific and Technical Information Exchange, or STIX (www.stixfonts.com). "The display of math symbols in publishing has always been difficult, but those problems have only become worse with the Web."

The set of STIX fonts will work very much like the Symbol or Zapf Dingbats fonts in most applications, where users choose from a grid of dozens of characters. The STIX font will have the appearance of a Times font, but the characters will not look any different if a user switches to a different font, like Courier or Helvetica, Mr. Ingoldsby said. "The symbols will work with pretty much any font," he said.

Mr. Ingoldsby said most scientific characters lack "flavor" - they are quite plain to look at - so adding one of those symbols to a document composed using, for instance, a serif font, which has fine lines projecting from the main strokes of the letter, will not make the scientific character stand out. Designers are also adding the alphabet, numbers and other common characters to the STIX font, so, Mr. Ingoldsby said, there will be no need to switch between fonts.

"This is meant to replace the font which people use today called New Times Roman," he said.

About 200 characters of the STIX fonts are being finished each month, Mr. Ingoldsby said. So far, about half of the 7,000 characters have been completed.

With so many symbols, however, the STIX fonts could be cumbersome to use. The developers are working to come up with a method that will make it relatively easy for users to find the symbols they want. Symbols will probably be organized by type or subject, with the user selecting a category (and possibly a subcategory) from drop-down menus. A grid of symbols in that category will then appear, from which the user can choose the appropriate one.

Creating a new font set is a complicated process. First, developers must correctly copy the shape of each character. Then they must adjust its metrics, or how the character is positioned in the space in which it is supposed to fit. And finally, they must make another set of adjustments to be sure the character looks good on a computer screen.

William H. Mischo, head of the Grainger Engineering Library Information Center at the University of Illinois at Urbana-Champaign, said that the STIX project had the potential to solve a problem that dates back to the 1400's, when Gutenberg first conceived of movable type.

"The two biggest problems since then for properly rendering intellectual works have been tables and mathematics," Mr. Mischo said. "Here we are in the digital age and we're still having these problems."

Because math equations have been included in Web pages mostly as static images, as either a PDF or a graphics file, scholars have not been able to take advantage of many of the Web's distinctive research capabilities, Mr. Mischo said. For example, a mathematician cannot just plug a particular equation into Google and expect to find other scholars working on a similar problem, since the symbols in a graphic will probably not turn up in a search.

"For someone trying to read a scholarly publication, the current way of doing things presents difficulties," Mr. Mischo said. "You can't enlarge, you can't pull it apart and you can't search it."

The lack of a comprehensive font for math symbols presents aesthetic problems as well. The text in math publications is usually unattractive because publishers are often forced to cobble together a variety of fonts to create complex equations.

"Courier may have one set of math characters and Bookman may have another set of characters, but they are not going to look good together," said Paul Topping, president of Design Science, a company in Long Beach, Calif., that makes an equation editor for Microsoft Word. "STIX will be a coordinated set of fonts that are meant to work together."

Of course, new ideas are always being developed in math and science, and some require new symbols. Mr. Ingoldsby, of the American Institute of Physics, said STIX will be updated when new characters are created.

"We're trying harder to work with authors so they come up with something new only when there absolutely has to be something new," he said.