The Use of Digital Photography in Civil and Criminal Cases
When deciding to utilize digital photography or digital image enhancement, the following issues are usually raised:
- What are the advantages of digital imaging?
- Can this technology be used in court?
- What is the most efficient and secure workflow?
- What protocols should be developed?
- What level of image security or authentication is needed?
The Advantages of Digital Imaging
Digital imaging can be used in the areas of digital photography, image enhancement, image analysis, and digital presentations. There are distinct advantages to this technology in all of these areas:
In digital photography, we get instant feedback regarding the content, exposure and focus of our images. If we find that we have underexposed the image, we can instantly take another with the necessary adjustments. In essence, there is no longer any excuse for poor photography! Even a well-exposed, properly focused photograph from a low-end digital camera will be better quality than an incorrectly out-of-focus photograph from the best film-based camera.
Image enhancement techniques offer the ability to discern previously hidden information in an image. For example, you can: make a formerly unidentifiable fingerprint image into an identifiable one; use frame-averaging techniques to make a noisy, valueless video into a clear, still photograph; or bring out shadow areas to show details that could not otherwise be seen. Basically, image enhancement allows us to have total control of the quality of our images.
With image analysis, we can compare objects in two different photographs and determine if they are the same, or we can analyze an image to determine if it has been altered.
In addition, digital presentations are easy and effective. Digital images can be printed and used as evidence in the same way as film-based photography, or they can be output to a CD and presented in court with a projector or large screen monitor. Photographs of crime scenes or accident scenes can be stitched together to create interactive panoramas.
The Acceptance of Digital Imaging in Court
Digital images have been presented in court since at least 1991. Thousands of police agencies and civil evidence photographers are using this technology daily without challenge. These photographers use digital imaging for photographing evidence, crime scenes and traffic accidents; enhancing fingerprints, video and other images; creating crime scene panoramas; and presenting evidence in court.
However, this technology has been challenged in Kelly-Frye hearings in two cases (Commonwealth of Virginia v. Robert Douglas Knight, 1991; State of Washington v. Eric Hayden, 1995). In both instances, digital imaging technology (and digital enhancement) was allowed, and in the Hayden Case, this ruling held up on appeal in 1998.
Many states and the federal government have revised their rules of evidence to address digital imaging. The Federal Rules of Evidence state in Rule 1001-Section 3:
“Original. An ‘original’ of a writing or recording is the writing or recording itself, or any counterpart intended to have the same effect by a person executing or issuing it. An ‘original’ of a photograph includes the negative or any print from the negative. If data are stored in a computer or similar device, any printout or other output readable by sight—shown to reflect the data accurately—is an ‘original.’”
The combination of peer acceptance, court acceptance, widespread usage, lack of challenge, and rules of evidence show that this technology is readily accepted in court.
Developing an Efficient and Secure Workflow
Mimicking the workflow of film-based photography and video is the best way to approach a digital imaging workflow. Digital imaging is a photographic process that substitutes electronic processing for the chemical processing of traditional film. It uses the same technology as video, except that the data is stored on digital media rather than videotapes. Even its role is the same as that of film-based photography or video: to provide visual evidence.
Digital workflow generally begins with maintaining a photo log. With digital imaging, this photo log can be a coin envelope that includes the case number or name, date, name of person taking photographs, and any necessary description. Upon completion of taking the photographs, the digital media can be put in the envelope, sealed, and turned in to the person or section responsible for processing images. The images are then moved from the digital media to a workstation computer hard drive, server, CD or other location for archiving casework. The folder containing these images can be named to reflect the case number or name. The media can now be reformatted and made available for re-use. The images should be backed up, and it is wise to use a RAID drive for storing the “live” images.
How to Develop Digital Imaging Protocols
Protocols and policies for digital imaging should reflect protocols and policies that deal with other types of evidence collection and visual evidence, especially video and photography. After all, digital imaging is primarily a photographic process that works with computer data instead of film or videotape.
For instance, we should have a method for keeping the chain of custody intact. This may be as simple as a method for turning in film/tape/digital media on a standard schedule (when the roll is complete, weekly, at the conclusion of each case, etc.). It may also cover where film/video is stored, who has access to it, and who is responsible for downloading the data.
In addition, we should keep records of the adjustments to images. When we make color or contrast adjustments in the darkroom, we rarely note what these adjustments are. It is likely that the only time any record of adjustments is made is when we do something unusual that we may want to repeat later. The same holds true for digital images. However, digital imaging offers a key advantage: it is easy to document data digitally, so we can more readily take notes on our procedures and adjustments.
What Level of Security is needed for Digital Imaging?
As with protocols and workflow, security for digital imaging should reflect security for film-based photography and video. Generally, this means that the computer where images are stored or accessed should be in as secure a location as the location where film and video are stored. If images are available on a network, the computers that have access should also be in secure locations.
At present, there is no court requirement that images utilize image authentication or security software. These types of programs can lead to problems: they often are inconvenient to use, and many of them actually alter the images by adding a watermark to them.
Courts simply require that images be accurate representations of what they represent—not that they be protected with some level of security software.
There are tremendous advantages to using this technology. Developing protocols and utilizing digital imaging can be a very straightforward process, reflecting the same approach as we use for film and video. Courts accept this technology daily and do not require that digital images be treated any differently than film or video.