While I certainly agree with Mike that flash should cause no harm for most materials (in fact, I've never heard that concern expressed before), I think the two reasons that are usually given by museums for not allowing flash photography (and the use of tripods, for that matter) are: 1. it may be (is) distracting to other visitors--probably a valid point for art museums, but certainly less valid for history and natural history, and 2. some sneaky image user may be able to make a good enough copy of some valuable artifact to publish it (and thus make lots of money) without paying the museum its normal photo and/or reproduction fee. My view of the latter point is, I am sure, of no interest to the original poster (it has never been of any interest to the administration of any organization I have ever worked for), but these are the reasons I have always heard for the photographic prohibition. Neither should apply in a situation like a wedding in a historic house. Later. David David Haynes, Institute of Texan Cultures, PO Box 1226, San Antonio TX 78294 Voice: 210/558-2248, FAX: 210/558-2218, InterNet: [log in to unmask]