I’ve been to a ton of museums that have said flash photography damages the works, but it seems like it’s not exactly true. “300 amateur flashes a day is equivalent to adding five minutes to the display day. In order to actually increase damage by 10% on a ten hour day, one would need to experience 3600 flashes per day. Two large professional flashes would raise the ante a little, they would need 225 flashes a day to add 10%. For museums at 150 lux (15 footcandles) these numbers become 10,000 amateurs, or 700 pros, every day. To actually double fading would need 100,000 amateurs a day. Most museums would kill for those attendance figures!” Sounds like a good MythBusters thing too, Full story here – Link.
Flash Bulbs and Artifact Preservation: Myth Debunked!