As with many areas of emerging musical practice, there are a number of different (some might say competing) approaches to representing microtones in music notation, and perhaps one of the most elegant is Sagittal microtonal notation, developed by George Secor and Dave Keenan. Sagittal is so named because its symbols are arrow-like (the creators had Sagittarius, the astrological archer, in mind).
Composer Jacob Barton wanted to use the Sagittal system in Sibelius, so using Sibelius’s built-in ManuScript programming language, he’s written a plug-in to do that, called Sagibelius, and he’s made it available for everybody to download. Jacob says:
It was a long journey to completing this. I wrote the plugins initially in 2005, but updates in the Sagittal font rendered it incompatible with my version of Sibelius. It took five more years of intermittent struggling with fonts to come up with a special version of the font which works for Sibelius. The original plugin was written for the Spartan subset of symbols, but the higher-precision Athenian set, capable of notating pitches to 3-cent accuracy, was requested. Parts of the process were laborious and will likely remain so for future updates.
If you use the plug-in and enjoy it, I’m sure Jacob would be very grateful of a donation or two in recognition of his hard work.