In other words, they’ve talked themselves into a belief, based on talking to themselves about their belief. Evans points out the irony that, “Curators ban photographing things like Pharaonic Egyptian relics that have been bathed in the intense UV light of desert sunlight for over 3000 years.”
Another reason given for the prohibition is the concern for copyright violation. However as Martin Evans points out: “Copyright laws vary from one country to another, and are notoriously difficult to interpret. In some cases, a museum or art gallery might be using the copyright argument as a smokescreen to hide a general desire to prevent visitors from taking photographs.”
What then are the reasons for prohibiting all photography and flash photography in particular?
One reason, told to photographer Paul Harcourt Davies by a museum guard, was that photography was banned to keep crowds moving. At a popular exhibit, people wait on line for hours and any photography slows down the line. Fewer people can get in to see the exhibit and revenue is lost.
There is another very real reason to ban photography: gift shop sales. Most museums make a substantial amount of their revenue from the sale of postcards, posters and other bric-a-brac. The fear is that people taking their own photos, no matter how badly, are going to spend less at a gift shop.