Forensic dental photography 215
basic recommendation is to use the slowest film speed that will have the most
grain density for the lighting present. Problems caused by having the wrong
film or improper lighting may be minimized by bracketing the exposures
over a wide range of camera settings. The term bracketing means to expose
individual photographs in a range of f-stops and shutter speeds.
As the digital era of photography has evolved, the availability of photo-
graphic film and film processing labs has significantly decreased. Even
though many types of film are still available, fewer stores and camera shops
carry the special films that are used in full-spectrum photography.
Previously it was possible to have film processed in one hour; it can now
take a week or longer when the film must be sent to a commercial processing
lab. Specialized films such as infrared film or even black-and-white film can
take even longer, as fewer and fewer labs process these types of film.
The potential for a significant lag time between image capture and print
delivery can create a potentially catastrophic problem for the photographer
should the photographs need to be retaken due to fogged film, poor focus, or
improper lighting. If the injuries are on a living victim, they may have healed
and would no longer be viewable. In a deceased victim, postmortem degra-
dation probably will have destroyed aspects of the injuries that were present
when the photographs were taken. The net result would be no preservation of
the evidence and no chance to recover it.
Advancements in design and manufacture of modern 35 mm cameras
have greatly simplified film photography. These cameras have the capabil-
ity to photograph objects with great accuracy and precise color detail. As
discussed previously, the lenses have coatings and the flash units are filtered
to direct only visible light to the film. When handled properly, photographic
films record the images in remarkably sharp detail. The most critical vari-
ables to consider when taking film-based photographs are (1) the type of the
film and (2) the intensity of the light present when the film is exposed. While
the photographer has great latitude in film speed selection, films of ISO 100
are usually adequate for injury documentation with adequate light.
It may seem redundant to rerecord the injury with black-and-white film
when color film photographs of the same injury were just taken—or is it?
The human eye is very adept at seeing images in color. Because of the color
information processed optically by the retina, other important details of the
injury can be overlooked. When the injury is photographed in black and
white, the eye is not distracted by the color composition of the injury and the
normal surrounding areas. Consequently, this absence of color allows the
viewer to see more detail of the injury. The duality of image capture available
with digital cameras and imaging software such as Adobe Photoshop® allows
the photographer to see both color and black-and-white images from one
file, demonstrating one advantage of taking digital photographs instead of
traditional photographic film.