No adjectival form
The adjectival form of "compositing" -- itself a noun formed from a present participle -- does not exist. Imagine a sentence such as "that shot is more compositing than the previous one." Jim Stinson 23:38, 9 August 2007 (UTC)
No plural form?
Also, the plural form is purely theoretical. No one would actually say something like, "I've done many compositings."Jim Stinson 01:10, 12 March 2008 (UTC)