Sometimes it seems that a visit to an art museum or gallery is rigidly structured around a set of universal rules – no eating, no drinking, no touching the works, no crossing the possibly arbitrary lines on the ground, and perhaps most importantly: no flash photography. What is it that makes museums so fearful of the little burst of light? Can a flash really damage a work of art?

As an exhibition host at one of London’s leading art institutions, I encounter the photography ban every day. Pictographic signs notifying visitors are often ineffective and many will test their luck. It is at times exasperating asking visitors not to take photographs of exhibition text or shadows or gallery layout despite not being individual works. It is difficult to explain that though the marble sculpture is made of stone and therefore not sensitive to light like paintings and works on paper, photography is still prohibited. It is a losing battle, and one with seemingly little science to support it.

It is a proven fact that sunlight (more accurately UV rays) will damage a work by gradually fading pigments and inks over time. Delicate works are displayed in near darkness and significant sums of money have gone to the development of safe lighting to simultaneously allow works to be displayed in natural light while also protecting the fragile components. This is well and good and future generations will be grateful for the efforts, but most camera flashes contain little UV light.

Martin H. Evans decided to investigate the effects of camera flashes on samples of materials and pigments. His experiments were conducted using a naked (meaning without a UV filter) flash and a filtered flash that is most common on digital cameras and smart phones. The results showed that after more than a million flashes slight fading was evident on some of the samples using the naked bulb, though this is not entirely surprising considering the well-known effects of UV rays. The other samples, however, showed no change at all. Evans claims his research demonstrates that, “Curators, journalists, art-lovers and museum directors have been telling each other this (that flashes damage art) for years, and many gallery visitors concur.”

While there may be little scientific evidence to support the banning of photography, and in particular flash photography, other considerations, from the reasonable to the outlandish, also factor into the gallery rule. Perhaps one of the best reasons to prohibit flash photography is that it affects the other visitors in the gallery. It is difficult to see something properly with sporadic flashes of light temporarily altering visual perception.

Another reason often cited for the strict rule is that photography slows down visitor movement throughout a space, and in the world’s largest museums where thousands of visitors flock every day, decreased mobility can mean fewer visitors and thereby less profits. Museums benefit financially from prohibiting photography - without images of their own, visitors are more likely to purchase posters, catalogues, and most commonly postcards to commemorate their visit. In an ideal world, art museums would be free from concerns of profits and finances, but of course, this is far from reality and many museums derive significant portions of their income from gift shop sales.

Perhaps the most absurd of arguments involves anti-theft and anti-terrorism measures. It is believed that allowing thieves and terrorists to photograph gallery settings may aid in their crimes. This can easily be countered by citing the detailed maps and gallery plans provided both online and in print as well as the increasing number of online virtual panoramic tours. Surely such ruffians would glean more valuable information through these methods than digital photographs.

The various reasons stated for prohibiting (flash) photography have their merits, but scientifically speaking, there are much greater nightmares for conservators than flashes from cameras. Regardless, you can find me standing by the no camera sign repeating: “Excuse me, sir. Photography is not permitted in the gallery.”