Does flash photography really damage paintings?
August 14 2014
Picture: BG
Effectively not, and no more than normal light exposure, according to this paper by Dr Martin Evans. It's worth reading in full, but here are some key parts.
First, the National Gallery did a test in 1995 to see how pigments reacted to extreme and repeated use of flash. The answer was, not much:
These trials showed that 'fugitive' pigments deteriorated while on the walls of a controlled-light gallery at about the same rate as if a modest 'hotshoe' flashgun was fired at them every 4 seconds from a distance of about 4 feet [over a million times!].
Following these tests, the National Gallery decided that professional photographers could use flash when photographing their paintings. The crucial thing to note here is, as Dr Evans says:
In practice almost all small camera-mounted flashguns now incorporate a correction filter to bring the xenon light balance close to natural daylight. These filters also remove most of the UV wavelengths which conservators fear.
He goes on to note that the problem is even less of a concern for smartphones, which, no doubt, is how most gallery visitors will be taking photos (or selfies):
Many 'smartphones' include an illuminator that may be a tiny xenon flash, or a light-emitting diode (LED) that briefly flashes light onto the subject. It is hard to estimate the power of these little illuminators in terms of strict guide numbers, but the consensus is that they can be rated at GN 2 to GN 4. Clearly, flashes from 'smartphones' cannot be regarded as a conservation threat in any properly lit gallery.
He concludes:
Is it worth getting steamed up about such a tiny extra quantity of light, as far as pigment fading is concerned? Several photographers have already suggested that any trifling damage done by a few hundred of these little flashes in a day could be fully offset by closing the gallery and turning off the lights a few minutes early. A ban would be justified in rare cases, where large numbers of photographers might be taking many flash photographs very close to something that could reasonably be considered photosensitive. The more advanced (and expensive) cameras used by serious photographers also have a built-in flash facility. The flash units fitted in digital single lens reflex (DSLR) cameras have guide numbers in the range GN 10 to 14 - somewhat more powerful than those built into the small cameras. However, these DSLR and similar advanced cameras can now take photographs at such high ISO sensitivity settings that their users seldom need to use flash. Does the ban on photography in some galleries really reflect a genuine, though misplaced, fear of light damage, or is it part of a hidden general anti-camera attitude by some administrators?
[....]
There are therefore some plausible reasons why a museum or gallery might decide to ban the use of photographic flash. However, to prohibit the use of flash on the grounds that it will harm the exhibits is the least plausible reason of all.
Of course, I absolutely agree that flash photography should be prohibited in galleries and museums, not least for the disruption it causes other visitors. The point of this post is merely to rebut the widespread belief that flash photography kills paintings.
