Roger,

The museum I work at (as registrar) has a significant amount of our
collection in photographic materials.  What we do is ask people to donate
photographs that perhaps (for example) may be used in the present or upcoming
exhibition.  If they do not want to donate the original material we suggest
that they loan us the original materials and then we make negatives, color
lasers, reprints, and/or photocopies so that we have something to preserve in
the collection.  The photos that are on exhibit are not original material
anyway (for archival/preservation reasons).  Although we do like to have the
original in our collection, we know that is not always possible.

The museum has had in the past photo identification days where people are
asked to come in and help the museum identify photos from the collection.
They are also asked to feel free to bring in new donations and / or loans.
This has been pretty successful in the past.

Just a few ideas for you!  I hope they help.  I would also strongly suggest
using appropriate forms (loan agreements, gift agreements, etc.) for legal,
institutional, and organizational purposes.  Good luck!

Sincerely,

Ginger M. Young, Registrar