With some care, you can achieve professional results when photographing paintings and other artwork. Film based single lens reflex (SLR) and view cameras are the traditional tools for this form of photography, but digital cameras are also a viable option, and not only because you can check your results as you go. One of the most difficult aspects of photographing artwork is to get the camera square with the piece you are photographing. While this has previously required an SLR, the LCD display found on modern digital cameras is a good alternative, and the straight sides of the viewing frame are excellent for squaring up with the artwork.
A tripod will help in placement and allows a long shutter speed, which is more useful than opting for higher ISO to gain a faster shutter speed. This is one area of photography where grain and noise are definitely undesirable.
Distortion is also highly undesirable. The camera should be placed so that it is completely horizontal and vertical to the artwork. The lens should be centred on the artwork, and the film/sensor plane should be parallel to the plane of the artwork. This will avoid “keyhole’ distortion.
A “flat plane” lens is ideal but any good quality standard lens should give acceptable results as long as it is not opened up too wide: try to keep the aperture in the mid-range (about f5.6 to f8) to obtain best definition and avoid vignetting (darkening of the image edges). Do not use a wide angle lens as it will distort (curve) the edges of the artwork.
The most straightforward method is to shoot by available light on an overcast day. You may need to use a warming filter (81A) if you are using daylight film, or the overcast sky may add a bluish cast, but be aware that direct sunlight is damaging to art works and do not expose any work of value to it! Work indoors by diffuse window light instead. Colour fidelity is essential, so I suggest shooting in RAW for most control if using digital.
Even, neutral lighting is essential for photographing paintings, tapestries, photographs and other 2 dimensional artwork. Diffused daylight is adequate, but controlled lighting offers greater control and flexibility.
Lighting - Hot photofloods are a poor choice. Apart from being expensive, their colour quality degrades rapidly. Photographic quality quartz lights with a reflective umbrella and barn doors give you the ability to direct and shape the light. Reflectors let you to soften the light when you photograph art which has any raised edges or texture, which could catch the light.
Construction grade tungsten lights with 1000 watt bulbs and individual stands are a viable and less expensive alternative.
Setting Up the Lights - Set the lights at approximately 45 degrees to the surface and slightly higher than the centre of the artwork. Keep the film/sensor plane of the camera parallel to the art piece and set the lights to either side of the camera.
It is important to make sure that the light is evenly distributed edge to edge and in the centre of the piece with no hot spots. Take readings with an incident meter is possible (see my Intel on using your camera as an incident meter). If you do not have one, use the camera in spot metering mode and check at various points on all sides, each corner and in the centre. Using soft boxes or placing thin pieces of polystyrene a few inches in front of the lights can greatly aid in evening out the light.
Copy Stand - A tripod is the most versatile method of securing a camera, but a purpose-built tabletop copy stand, supplied with two or four lights is excellent for works which are not too large. They can also be purchased without lights, and simplify camera positioning and lighting considerably.
Tripods - Artwork that is too large for a tabletop setup benefits from a sturdy tripod. Pay as much attention to the head as to the legs. Too light a head will sag or shift just enough to spoil your work but not enough to notice until you see the enlargements and can’t go back to reshoot!
There is no point in using a tripod or stand if you cause vibration when you release the shutter. Use a remote control or a cable release. If you don’t have one or your camera will not accept one, use the self timer. If you are using an SLR and vibration is still a problem, use mirror lockup.
Other Considerations - Bracketing your exposures is good practice, but don’t let the camera make the consecutive exposures in a burst - you will induce vibration. Make each separately in intervals of 1/3 to ½ a stop.
Glare will ruin your pictures. You will encounter the problem most with oil paintings, with pictures under glass and other shiny surfaces, and when the surface is uneven. While glass can induce glare, it can also be used to reduce or eliminate it, by holding the surface flat. This is not practical for works that are hung, but shielding the lens with dark card or black velvet and covering nearby reflective surfaces can help.
A Polarising filter can be placed over the lights. You'll need a separate stand with a clamp to hold the filter in place in front of the light (Not too close: the plastic melts!).
A polariser fitted to your camera, either alone or in conjunction with the light polariser, should be part of your standard equipment.
Finally, the same pieces of translucent material suggested above to even out the light also are effective in reducing glare (technically referred to as “scrims”) because the diffuse light the produce is not sufficiently directional to reflect from the artwork.
