-------- Original Message -------- Subject: Invisible property stamps? Date: Wed, 4 Sep 2013 00:46:14 +0000 From: Weessies, Kathleen <[log in to unmask]> To: [log in to unmask] <[log in to unmask]> Lately I've been reading about map library practices for marking maps, particularly rare and valuable maps. Once in a while in the literature there is a mention of invisible property stamps that only show up in certain lighting. I haven't met anyone who uses this kind of stamp (or maybe I did and it is a closely guarded secret!). Anybody have any comments on this practice? Kathleen Weessies Geosciences Librarian Head, Map Library Michigan State University 517-884-0849