I suppose there is some sort of lux-hour formula. Typical modern
electronic flash units fire at 1/1000 to 1/5000 second. Granted, they
are somewhat intense, but it takes 5000 flash photos to equal one
second of exposure to such light. Surely the *hours* of lower level
ambient light are more detrimental to the artifacts. Flash photography
would seem a drop in the ocean.
   Christopher Bobbitt
   Curator of Collections, Monroe Co. Historical Museum
   Bloomington, IN
   [log in to unmask]