There are several reasons why visitors to museums are frequently asked not to take flash photographs. The primary concern is the preservation of the art, as flash photography, especially when done in large quantities, can cause significant damage to works of art. Some cynics have speculated that the prohibition on taking flash photographs is motivated a desire to protect gift shop revenue, but this is not the case.
Flash photography has the potential to accelerate the deterioration of a work of art. Light and heat are produced flashes, which can cause a variety of chemical reactions. As anyone who has left a photograph in a sunny window for a few months knows, exposure to light and heat causes the cellulose in paper to break down and damages many pigments. While a single flash is not a significant issue, a series of flashes over the course of years of exhibition will hasten the deterioration of a work of art. As a result, policies prohibiting flash photography in museums are being developed so that future visitors can enjoy the art as well.
The environmental conditions in museums are also explained concerns about light and heat. The majority of reputable museums are built in such a way that sunlight never reaches the artwork, instead using specialized low-level lighting that allows visitors to view the artwork without damaging it. To prevent heat or temperature fluctuations from damaging the art, the air is frequently kept cool and at a consistent temperature.
There are a few other reasons why flash photography is prohibited in museums. For one thing, flash photography can be very upsetting to other customers, particularly those who have medical conditions that cause them to be more sensitive to light. Flash photography can be considered disrespectful in places of cultural and artistic value, such as cathedrals. Using flash photography during events or ceremonies in museums is also considered disruptive, as flashes can be very distracting.
Many museums, however, have recognized the desire to photograph their collections. As a result, many people now allow photography as long as no flash is used. To compensate for the low lighting conditions, photographers should use a tripod, and they should try to be respectful of other patrons while photographing their favorite works of art.
Due to copyright concerns, or at the request of an artist or the owner of a loaner collection, some museums prohibit all photography. Taking photographs in these situations may result in a polite request to leave the premises.