Regarding lighting:
When Michelle Terrell and I were studying a Jewish cemetery in the Caribbean, we
used a squirt bottle to lightly spritz the stones with plain water. The
differential drying allowed a few moments while a photo could be taken (in just
about any light) that highlighted the worn inscriptions. As Ron mentioned with
his snake, we also found some details on the stones that hadn't been visible
before. A real advantage was the expanded flexibility in scheduling photos.
Obviously, it was even more low impact than the rain.
Eva Terrell
Historic Preservation/Cultural Resource Management/Archaeology
Collaborative Design Group, Inc.
Minneapolis, MN 55454
p:612-371-6410
f:612-332-3626