I recently wrote to PaleoNet, the paleontologic listserver, with a question
on how to go about labeling photographic slides. I received half a dozen
replies, mostly private. Here is the gist.

The information associated with the slides is more important than the
numbers assigned to them. Information such as the date, place, taxa, and so
on can be entered into a database (e.g., Microsoft Access) just as for
collections of shells, books, or anything else. It is most important to
consider the ease of retrieving information, and what type of information is
to be retrieved. (Obviously, the most important thing is to label your
photos soon after they are developed; as everyone knows, an old photograph
without information can be intriguing but is not worth much as a historical
document.)

Catalog numbers should be unique, but the exact numbering scheme is not as
important as getting the fields of the database right. For example, numbers
can reasonably be assigned (1) sequentially or (2) by date (and then
sequentially within that date). If you set the database up properly, you can
then search for "San Salvador" or "Trivia sentina" or even a particular
date.

Slides can be barcoded if you have the right equipment, which can sometimes
be obtained secondhand from a library.

Andrew K. Rindsberg
Geological Survey of Alabama