# Museum photography

Museum photography involves producing photographic reproductions of objects on display in museums: utilitarian objects, 2D or 3D works of art. This is of capital importance for enriching Wikimedia projects, but involves difficulties of a technical, legal and psychological nature.
As it involves faithful representation of fixed objects, museum photography is close to studio photography, especially in the intended aim: a "perfect" image, as sharp as possible and as high resolution as possible. A slightly unsharp action photograph would be acceptable, but an unsharp museum photograph is best avoided. High quality museum photography is difficult without an appointment, special lighting and open displays, but it is possible.

## Authorisation and equipment limitations

The position of museums as regards to photography varies over a large spectrum, but is generally characterised by a few rules and restrictions of photography.
Some museums forbid any form of photography. There is no need to argue in this case, since the personnel have orders and rules to enforce, have no say in the elaboration of said rules, and will throw you out if you don't comply with their orders. Photography is rarely allowed in temporary exhibitions, especially those containing objects lent from other collections. There are valid copyright concerns for works still in copyright.
Most museums which do not prohibit photography per se do so under the condition that you use no flash, or specify this in certain galleries. The interdiction is justified by:
* preserving the comfortable experience of other patrons whose visit might be compromised by your flashing photographic strobe lights,
* the possible deterioration caused by the broad spectrum, instantaneously powerful flash energy. Intense light may age pigments and chemically unstable substances, such as glue. Some of the photons of the flash's light excite electrons of the atoms on the surface of the object or just below and alter their chemical state, which accelerates aging.
* historical reasons dating back to the time when flashes constituted an actual fire hazard.
In any case, accurate flash photography is a difficult art to master. In particular, the flashes of small cameras often yield horrendous results, as they throw their light from too close a point from the lens, and parallel to it, without diffusion. Hence, banning of flashes is not as much of a hindrance as is generally thought.
Most museums also forbid using tripods or monopods. This prevents you from appropriately stabilising your camera during longer exposure times than can be accomplished hand holding a camera. Selecting a camera with an appropriately tested anti camera / photographer shake compensation system may improve the clarity of captured images while hand holding the camera in indoor "available" light.
If you can't use a support, you can reduce camera movement considerably by:
* standing perpendicular to the direction you are aiming, with your feet at least shoulder-width apart.
* pulling your elbows in tight to your chest to form a cradle for the camera with both hands
* remember "BRASS" -- Breathe, Relax, Aim, Squeeze the shutter release slowly, Shoot while holding your breath.

## Technical aspects
### Exposure

Photography involves fixing a flux of light on a sensitive surface (a chemical film or an electronic sensor). We have control over three parameters:
* Aperture or lens diaphragm size: the size of the hole that lets light into the camera
* shutter speed duration: the amount of time the hole is open to let light in
* ISO speed, film/sensor sensitivity: how receptive our capture medium is to recording the light that hits it
An ideal final image is as sharp and clear as one might observe in person, and has low noise (digital) and or grain (film), which suggests a lens aperture diaphragm size of about f/8 or smaller, and a low film/sensor sensitivity for low grain or noise. The duration of the shutter opening during exposure should be quick enough to prevent capturing any motion blur (subject motion or camera/photographer's motion due to shaking a hand-held camera).
Museum lighting may be insufficient to permit capture with the highest qualities, so some compromises may have to be made:
* hand-holding instead of a tripod,
* available light instead of flash,
* use of wider lens aperture and or
* higher film/sensor sensitivity/settings.
Interiors of museum buildings are unusually dark by photographic standards, and museums are especially dark buildings.
In general, lack of light can be compensated in four ways:
* Artificial lighting such as flash or studio lamps. This is usually forbidden in museums, and is difficult to use (see references below on light management).
* Opening the lens aperture diaphragm wider. A larger aperture like f/1.4 will usually allow enough light through during an open shutter duration that is brief enough to reduce capturing subject or camera/photographer movement, even in the low lighting of a museum, but this may yield an unacceptably narrow depth of field focus, especially for three dimensional objects.
* Higher-sensitivity film or sensor, but may yield more grain and or digital noise.
* Slower shutter speed, which may require affixing the camera to be immobile during exposure. This is where museums that ban tripods becomes a problem.
Depending on the environment, you may need to employ one or all of the above tricks to capture a satisfactorily accurate exposure with minimum noise/grain. It is also possible to underexpose during capture and overdevelop later (film or digital - known as push processing), but be aware that this usually increases noise/grain.
* A good image: f/32; 30 second exposure (tripod); ISO 100; post-processing to remove dust, hot pixels, and disturbing context.

### Practical cases
#### Bidimensional works and diaphragm aperture

Bidimensional works of art, such as paintings, do not require a large depth of field. It is possible to open the diaphragm to around f/4 and gain some light. The light thus gained allows to lower the sensitivity of the sensor, and hence digital noise.
Paintings often reflect light. One way to overcome the problem is to take photographs from an angle, and correct the perspective in post-processing (this also works when using flashes).

#### Tridimensional objects: fixing the camera body

For tridimensional objects, it is capital to have a sufficient depth of field, to avoid cases like a statue with the tip of its nose sharp and its body blurred. This kind of case is especially problematic in proxiphotography. Even by raising the sensitivity of the sensor (and thus the noise level), little can be done to compensate the problem apart from fixing the camera.

##### Fixing the camera body

In the absence of a tripod the camera body can be fixed upon many items in the museum: doorframes, tablets, stands or fences. The small fence masts which hold ropes in front of works make excellent stands for cameras. It is possible to orient the camera both in elevation and azimuth (vertical and horizontal angles).
Most of the shaking of hand-held photography disappears when one of the three dimensions of space is constrained. Hence, a tripod is better than a monopod, but a monopod is much better than just holding the camera.

##### Display glass

It is possible to press the end of the lens directly against displays. This will both cut out most reflections in the glass, and provide a stand for the camera. On the other hand, the distance to the subject is then fixed: the focal length and the minimum focusing distance must be adapted:
* a macro lens might be in order to achieve focus on close objects (either small ones, or details of bigger ones)
* a wide angle lens would be needed to capture the entirety of a bigger object. In the case, beware the deformations induced by very wide angle lenses.
Beware of lenses which change their length when focusing or zooming. Ideally, you should be able to zoom or focus after setting the camera in place. It might be advisable to use a lens hood so that the end which touches the display does not move with respect to the camera body.
Another way to reduce reflections is to use a polariser. This will cost you one and half stops of light, so using a tripod may be necessary.
* Zea does it on fence masts
* Zea does it against display windows
In the case of horizontal display glasses, the camera can be put directly on the glass, which then serves as a support. Motion blur is further avoided by setting the camera on Timer. Reflections are minimised by the camera leaning directly against the glass, and further reflections can be canceled by placing one's body or hands as to eliminate undesired incomming light. Depending on the camera type, a variety of angles can be obtained; other objects, such as lens hoods or pencils, can be used to tune the angle and distance of the camera with respect to the glass.

### Equipment

If purchasing equipment for museum photography, get stabilized equipment whenever possible. Stabilization gains about three stops on the otherwise slowest shutter speed, making it possible to take images up to 1/15th of a second with negligible risk of vibration blur. Avoid using high ISO, sometimes advertized as "digital stabilization", as it reduces image quality.
Among interchangeable-lens cameras (SLR, ILC): Canon (IS), Nikon (VR), and Panasonic (OIS) systems have stabilized lens models, while Olympus, Sony, and Pentax systems have stabilized sensor camera bodies. Compact and bridge cameras are widely available with sensor or lens stabilization. Stabilization effectiveness varies from two to four stops, depending mainly on the manufacturer.
Fast lenses (large maximum aperture) are very helpful. Most interchangeable-lens cameras have affordable unstabilized 50mm prime lenses (fast and compact) that were historically the kit lenses of the respective film SLR systems. These work great, especially when mounted on stabilized-sensor camera bodies.
The focal range of choice for museum photography is the "standard" alias "normal" range. It is advisable to pack mild wide-angle lenses for large objects, since ability to move backwards is limited; and macro lenses, for smaller objects and for closer focal distance.

### White balance

Learn how to set a custom white balance on your camera, and carry a white piece of plastic or cardboard for reference. Using a correct white balance will save considerable amounts of time during post-processing and help avoid possible errors. See , and for examples and support.

## House rules: legal and psychological aspects

Museums may have internal regulations, known as "home rules", which forbid any "serious" or commercial usage of images taken without a special permission. Hence, they do not authorise photographing for Wikipedia.
Prohibitions against photography (and publishing) are often inappropriate and unenforceable. In most countries, a work such as your photograph is owned by whoever creates it, and can be used as the creators see fit. So if your photograph is not a derived work of an artifact or artwork covered by someone else's copyright, then the photograph and its copyright are yours, and no one else has superior rights over your photograph. Commons does not enforce or support any museum's own "home rules".
In some countries, jurisprudence has explicitly ruled that possession of a good alone gives no right to its representation. Hence, while it is possible to challenge the publication of photographs in court if the publication compromises one's private life, there is no strong case merely if someone possesses the object photographed. But publication rules have nothing to do with your visit to a museum to make your own photographs.
Museum personnel may ask questions regarding future use of photographs, especially when one is using what may appear to be large or expensive equipment capable of making images with high qualities of clarity and precision, such as
* "What are you taking photographs for?"
* "Are you publishing a book?"
* "What are you going to do with those?"
... and so on. In no case should one feel compelled to answer these questions. Stating that one is taking photographs for Wikipedia will probably yield incomprehension, lengthy and disagreeable discussions, and interdiction of your photography, even confiscation of your camera, film, or memory cards. Limit oneself to saying that the images are for personal purposes. Try something like this:
* "I'm so overwhelmed by all the beautiful things I'm seeing on my vacation, I want to cherish everything I see and remember these moments as long as I live, especially when I'm old and can't afford to travel anymore, like my poor grand parents, who blah, blah, blah ..."
That your unsaid personal purposes may eventually involve offering the images to the public by putting them on Wikimedia Commons is none of their business. Indeed,
* someone in authority demanding answers to such questions is invasive (and impolite),
* in most jurisdictions, museum guards have no rights superior to you as they are not police officers, and
* the question stems from their erroneous premise that the museum can stamp a de facto copyright on public domain work. They may try to prohibit photography in their space, but their only remedy is to evict you for trespass. They have no superior rights to your images. They themselves cannot impose further restrictions on the subsequent use of your own copyright photographs since they have no ownership or copyright of your photographs, even if you make photographs in an area where someone else thinks photography is prohibited.
A museum employee may claim that an implicit contract, subscribed by purchasing the entrance ticket (Note that some museums are free and hence do not sell tickets), was broken when you photographed (read the fine print during a separate visit before the day you plan to photograph). However, the museum would probably have to prove to a judge that there was damage, especially if their "ban on serious use" is not clearly elaborated or made plain and comprehensible in writing.
Plan to avoid confrontation by separately (even anonymously or pseudonymously)
* getting any policies in writing before your visit, review them, and challenge them, if appropriate, as a separate encounter from your photography visit.
* or plainly request special authorisation to take photographs for further publication on Wikimedia Commons. This way you may also be permitted to use a tripod.
If their guards are then forewarned not to harass photographers, your subsequent visit will go smoothly. Both we and the museums have a vested interest in these images being made, and shared, and some museums will be receptive to the idea.
On the other hand, many museums' anti-photography rules exist to prevent the objects in question from being damaged by being photographed. This is related to preservation, not intellectual property law. Unfortunately, it can prevent images of the objects from being uploaded to Commons. As for images of objects on display in museums found on museum websites, per c:COM:ART, images of 2D objects are okay to upload but images of 3D objects are not (without permission).

## Documentation

It is important that every photograph be appropriately labeled. A proper label should include
* the name of the work and a short description;
* the name of its author, if known;
* the date and location of its making;
* its dimensions and the material out of which it is made, and
* a museum reference number, an access line or the location of the display within the museum.
This information is often on display on labels next to the work itself. Photographs of these labels should be taken to allow further labelling on Commons. Such labels may be independently copyrighted and are often not suitable for Commons themselves. Rather, these labels are typically transcribed in the description of the relevant image on Commons.