Can we exhibit a flashing controversy through a scientific lens?
By Tori Bell '26 - Acton-Boxborough Regional High School
Since 2010, the National Archives in Washington, D.C. has banned visitors from photographing any exhibit in the museum. But, what is the scientific process behind this? And most importantly, what is up with all the controversy?
Many museums, particularly the National Archives, prohibit visitors from taking photos of any of the exhibits. Usually, they say it is because flash photography can hasten the damage on the artifacts, and they are fearful that people can forget to turn off the flash on their cameras. However, if you look beyond this excuse, there is a better explanation to both sides.
As much as we want our cherished artifacts to stand the test of time, it is only natural that they experience the effects of deterioration, whether it takes months or millenia. The effort to preserve artifacts is especially linked to museums, which exist for the purpose of keeping, sharing, and informing these vital pieces of our history for us and for future generations.
However, an especially powerful force that hastens the deterioration of these exhibits is light. According to the book Effects of Light on Materials in Collections: Data on Photoflash and Related Sources by Terry T. Schaeffer of the Getty Conservation Institute, artifacts found in museums have the potential to be altered when absorbing light, which is a form of energy.
“Only light energy absorbed by a material can cause a photochemical change in that material. But absorption of light does not guarantee that a chemical change will follow. To consider the absorption of light energy by substances… a molecule will absorb a photon if the energy of that photon is exactly or… nearly equal to the difference between two energy states of the molecule,” wrote Schaeffer.
Since the molecule has extra energy from being in an excited state, there needs to be a way to “use up” all of this extra energy. One possibility is that the molecule can reemit the energy as glowing light. Another is that all of the energy gets converted into heat. A third result is that the energy can be transferred to other molecules, or the state could lose part of the energy and transform into a state with less, but longer-lasting energy. The final possibility is that in a molecule with high amounts of energy, the bonds between atoms can break.
Schaeffer states that the molecule will only be chemically altered if the last possibility happens. This means that it is uncommon for a chemical change to occur when an artifact is exposed to light, but it is still a possibility.
After knowing how the material absorbs light energy, to see if light can significantly alter an object, comes quantum yield. In other words, quantum yield is equal to the number of times an event happens divided by the total number of photons that are absorbed, and in most cases, by the materials used to make artifacts.
“When light interacts with matter, a large number of photons and molecules are involved even when the mass of the substance is small because of the small size of individual molecules,” wrote Schaeffer.
An example is, if 1,000,000 molecules can each absorb a photon, and if 100 of them can be altered chemically, then the quantum yield will be 100 1,000,000 = 0.0001, or 0.01 percent. The chances of an object being chemically altered are uncommon. When this happens, there will be low quantum yield in the photochemical reaction. The lower the quantum yield is, the less likely light is to damage the object, and vice versa.
“In general, to determine whether light striking an art object will cause a significant change (i.e., damage) in the object, we must know (1) whether the light energy is absorbed, and (2) what the quantum yield is for subsequent photochemical reaction,” wrote Schaeffer.
So is the amount of light produced from camera flashes enough to cause noticeable damage to the artifacts? According to the website for the National Archives in Washington, D.C., the documents were exposed to around 50,000 flashes a year. However, it would be difficult to know how powerful those flashes are, given the variety of flash strength in cameras the visitors are using.
The National Archives also claims that artifacts are “fragile and subject to fading from light,” and according to an article from ScienceDirect by Martin H. Evans of Cambridge University, some museums claim that the artifacts can fade as the amount of camera flashes add up.
“You don’t want any UV in your light source, ever [because then], you would ruin the art, and for no good reason.” said Aurelien David, a scientist who works for LED development company Soraa, in an interview with Wired Magazine.
Additionally, according to a study conducted by the Royal Society of Chemistry, light exposure can alter certain artists’ pigments, which causes them to become discolored. Vincent Van Gogh’s sunflowers painting is a prominent example of this deterioration. When lead chromate (or chrome yellow) is exposed to light, it darkens and changes the pigmentation of the paint.
But, even though Van Gogh’s collection of sunflower paintings have sustained damage from light over time, what exactly is causing this damage? There are many myths that flash photography damages objects, but that does not necessarily mean that the damage stems from flash photo-taking. Rather, light exposure in general, including the lights from inside the museums, contribute just as much.
“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,” wrote Evans.
Evans believes that the flash used by the general public poses little risk to most of the exhibits present in museums. In “Amateur Photographers in Art Galleries: Assessing The Harm Done by Flash Photography”, Evan assesses the harm done by flash photography. He points out that curators give the same reason for banning the photography of relics like Pharaonic Egyptian artifacts that have been bathed in extreme UV desert sunlight for over 3,000 years. This supports the stance that the impact from the flashes from museum visitors is minimal when compared to the conditions that the artifacts were in for millenia.
The fear of flash photography damaging museum artifacts originates from the danger it once held. According to Evans, when the first flash lamp was first created in 1887, it caused an explosion of bright light, sparks, and smoke by igniting a spoonful of magnesium metal powder. This led to museums to stray away from allowing them to be used in galleries. By the 1930s, flash still carried a risk for fire hazards, so the rule continued to be enforced by gallery curators.
“Compact inexpensive electronically controlled flash units…were widely available to amateur photographers [in the 1970s]. As their use spread, museum professionals became concerned,” wrote Evans.
This is how misconceptions about flash photography usage arose. Evans asserts that the idea of flash “freezing” the movement of objects was a phrase in journalism that was sometimes taken too literally and that journalists may have gotten the idea for this phrase because of how flash lasted for about a few milliseconds. Another concern also includes the impact of copyright laws.
"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,” writes Steve Meltzer from Imaging Resource.
According to Evans, other possibilities may include museums wanting to boost the sales in their shops, flashes triggering alarm systems, and flashes carrying security risks such as planning theft or terrorism. However, he makes the rebuttal that this position would be unlikely since its flaws have been pointed out on several forums and websites for photography.
“There are… 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," writes Evans.
However, when it comes to what artifact preservation means for society, the Archive’s website promises to offer a balanced commitment to make these documents available to the general public with the need to preserve and protect them for the future.
Many museums, particularly the National Archives, prohibit visitors from taking photos of any of the exhibits. Usually, they say it is because flash photography can hasten the damage on the artifacts, and they are fearful that people can forget to turn off the flash on their cameras. However, if you look beyond this excuse, there is a better explanation to both sides.
As much as we want our cherished artifacts to stand the test of time, it is only natural that they experience the effects of deterioration, whether it takes months or millenia. The effort to preserve artifacts is especially linked to museums, which exist for the purpose of keeping, sharing, and informing these vital pieces of our history for us and for future generations.
However, an especially powerful force that hastens the deterioration of these exhibits is light. According to the book Effects of Light on Materials in Collections: Data on Photoflash and Related Sources by Terry T. Schaeffer of the Getty Conservation Institute, artifacts found in museums have the potential to be altered when absorbing light, which is a form of energy.
“Only light energy absorbed by a material can cause a photochemical change in that material. But absorption of light does not guarantee that a chemical change will follow. To consider the absorption of light energy by substances… a molecule will absorb a photon if the energy of that photon is exactly or… nearly equal to the difference between two energy states of the molecule,” wrote Schaeffer.
Since the molecule has extra energy from being in an excited state, there needs to be a way to “use up” all of this extra energy. One possibility is that the molecule can reemit the energy as glowing light. Another is that all of the energy gets converted into heat. A third result is that the energy can be transferred to other molecules, or the state could lose part of the energy and transform into a state with less, but longer-lasting energy. The final possibility is that in a molecule with high amounts of energy, the bonds between atoms can break.
Schaeffer states that the molecule will only be chemically altered if the last possibility happens. This means that it is uncommon for a chemical change to occur when an artifact is exposed to light, but it is still a possibility.
After knowing how the material absorbs light energy, to see if light can significantly alter an object, comes quantum yield. In other words, quantum yield is equal to the number of times an event happens divided by the total number of photons that are absorbed, and in most cases, by the materials used to make artifacts.
“When light interacts with matter, a large number of photons and molecules are involved even when the mass of the substance is small because of the small size of individual molecules,” wrote Schaeffer.
An example is, if 1,000,000 molecules can each absorb a photon, and if 100 of them can be altered chemically, then the quantum yield will be 100 1,000,000 = 0.0001, or 0.01 percent. The chances of an object being chemically altered are uncommon. When this happens, there will be low quantum yield in the photochemical reaction. The lower the quantum yield is, the less likely light is to damage the object, and vice versa.
“In general, to determine whether light striking an art object will cause a significant change (i.e., damage) in the object, we must know (1) whether the light energy is absorbed, and (2) what the quantum yield is for subsequent photochemical reaction,” wrote Schaeffer.
So is the amount of light produced from camera flashes enough to cause noticeable damage to the artifacts? According to the website for the National Archives in Washington, D.C., the documents were exposed to around 50,000 flashes a year. However, it would be difficult to know how powerful those flashes are, given the variety of flash strength in cameras the visitors are using.
The National Archives also claims that artifacts are “fragile and subject to fading from light,” and according to an article from ScienceDirect by Martin H. Evans of Cambridge University, some museums claim that the artifacts can fade as the amount of camera flashes add up.
“You don’t want any UV in your light source, ever [because then], you would ruin the art, and for no good reason.” said Aurelien David, a scientist who works for LED development company Soraa, in an interview with Wired Magazine.
Additionally, according to a study conducted by the Royal Society of Chemistry, light exposure can alter certain artists’ pigments, which causes them to become discolored. Vincent Van Gogh’s sunflowers painting is a prominent example of this deterioration. When lead chromate (or chrome yellow) is exposed to light, it darkens and changes the pigmentation of the paint.
But, even though Van Gogh’s collection of sunflower paintings have sustained damage from light over time, what exactly is causing this damage? There are many myths that flash photography damages objects, but that does not necessarily mean that the damage stems from flash photo-taking. Rather, light exposure in general, including the lights from inside the museums, contribute just as much.
“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,” wrote Evans.
Evans believes that the flash used by the general public poses little risk to most of the exhibits present in museums. In “Amateur Photographers in Art Galleries: Assessing The Harm Done by Flash Photography”, Evan assesses the harm done by flash photography. He points out that curators give the same reason for banning the photography of relics like Pharaonic Egyptian artifacts that have been bathed in extreme UV desert sunlight for over 3,000 years. This supports the stance that the impact from the flashes from museum visitors is minimal when compared to the conditions that the artifacts were in for millenia.
The fear of flash photography damaging museum artifacts originates from the danger it once held. According to Evans, when the first flash lamp was first created in 1887, it caused an explosion of bright light, sparks, and smoke by igniting a spoonful of magnesium metal powder. This led to museums to stray away from allowing them to be used in galleries. By the 1930s, flash still carried a risk for fire hazards, so the rule continued to be enforced by gallery curators.
“Compact inexpensive electronically controlled flash units…were widely available to amateur photographers [in the 1970s]. As their use spread, museum professionals became concerned,” wrote Evans.
This is how misconceptions about flash photography usage arose. Evans asserts that the idea of flash “freezing” the movement of objects was a phrase in journalism that was sometimes taken too literally and that journalists may have gotten the idea for this phrase because of how flash lasted for about a few milliseconds. Another concern also includes the impact of copyright laws.
"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,” writes Steve Meltzer from Imaging Resource.
According to Evans, other possibilities may include museums wanting to boost the sales in their shops, flashes triggering alarm systems, and flashes carrying security risks such as planning theft or terrorism. However, he makes the rebuttal that this position would be unlikely since its flaws have been pointed out on several forums and websites for photography.
“There are… 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," writes Evans.
However, when it comes to what artifact preservation means for society, the Archive’s website promises to offer a balanced commitment to make these documents available to the general public with the need to preserve and protect them for the future.
Tori Bell is participant of the First to the Frontpage Summer of 2022 program.