In addition, there is no "color" in the UV and IR region so nothing is gained using color films. Second, the blue layer that does react does not provide as much contrast as black and white film. First, the top emulsion layer of all color film which is blue, contains UV blockers preventing the exposure of the bottom layers. For these techniques black and white film offers the best results. These techniques are useful because of the way our skin interacts differently with UV and IR light compared to visible light. Yet in domestic violence photography, UV and IR techniques are often used to see images that our eyes cannot see. Because documentation of evidence requires the reproduction to be as accurate as possible, color film is the best medium. Since print film offers considerable latitude in exposure, it provides a definite advantage for those who are not expert photographers. In addition, for use in trial situations, slides are more expensive to convert to enlargements than print film. This means that the exposure must be exact for the photo to turn out correctly. Slide film is not designed for print processing and thus lacks latitude. These corrections can be to print film through adjustments in the print processing. The drawback of using higher ASA film is that enlarged photos may appear grainy and less detailed.Īlthough slide film has accurate color rendition, it lacks "latitude." Latitude in photography is the ability to produce a good picture from a negative that is slightly underexposed or slightly overexposed. Faster film reacts quicker to light, therefore it requires less light for proper exposure. The higher the ASA number the "faster" the film. These degrees of sensitivity are referred to as ASA. Film has varying degrees of sensitivity to the amount and intensity of light. There are basically three common types of film: black and white, color negative and transparency. The range of infrared light close to the visible spectrum is also photographically reactive. Extending just beyond the visible region in the other direction from 700 nm and higher is the infrared region of light radiation. Therefore, it is possible to produce images that may only be observed using photography. Although we cannot see this light, it is reactive with photographic materials. Below violet from 200 to 400 nm is the ultraviolet region. The areas extending in either direction beyond the visible spectrum are the invisible regions of light. The visible region of the light spectrum ranges form 400 to 700 nanometers (nm) in wavelength. These wavelengths increase in the direction from blue to red along the length of the spectrum. Each color represents a different wavelength of light. The band of colors range from violet to blue, blue-green, green, yellow, orange, red and deep red. A beam of white light can be separated into the visible spectrum using a prism. Visible light, or white light, is a combination of all the visible colors. The colors that are visible to the eye represent only a small portion of the light spectrum, also known as the electromagnetic spectrum. In addition, affordability of the necessary equipment is a concern, and the illustrated techniques were developed with this in mind. The objective this article is to provide some basic knowledge of photography and illustrate four photographic techniques that have proven to be successful in domestic violence cases: color photography, alternative light source (narrow band light source) photography, reflective ultraviolet (UV) photography, and infrared (IR) photography. The pictures can be used in the event that the victim later becomes unwilling to testify. Therefore, the importance of documentation becomes relevant in preventing the recurring abuse of victims. If the abuser is only jailed temporarily after the initial arrest, it is possible for an abuser to coerce the victim into not testifying. Often, victims of domestic violence are dependent upon the abuser for food and shelter. When injuries resulting from domestic violence are promptly and adequately documented, it is possible for prosecution to occur without the victim's testimony. Documentation by photography is an important and powerful tool in the investigation of domestic violenceĬrimes.
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