The files can be named after an original source collection or per
project, depending on the needs of the local institution. Up to four
letters can represent the project abbreviation or original collection
name, e.g. hf for Harrison Forman Collection or sccl for Shawano
City-County Library. The remaining digits indicate a unique file
number. This is often simply sequential numbers prefaced with
leading zeros. For example, digital images from the Harrison
Forman collection project are named hf000001, hf000002, etc.
(p. 5-6)