Prepared for the Wisconsin
Department of Natural Resources
Wisconsin Department of Natural Resources
By Dave Edwards
Revised November 1, 2002
Wisconsin – November 1, 2002
?It is common knowledge that as to such matters, either through want of skill on the part of the artist, or inadequate instruments or materials, or through intentional and skillful manipulation, a photograph may not only be inaccurate but dangerously misleading.? Cunningham vs. Fair Haven & Westville R. Co. (1899)
Through time photographs have been challenged as legal evidence. Photographs produced from either negative or positive transparency film are time tested. Courts are familiar with photographs from film. Images from digital cameras are fundamentally different. Care should be taken to ensure digital images are not only allowed as evidence in a court of law, but that they also receive appropriate evidentiary weight. This article provides general recommendations on how to properly handle and archive digital images.
Digital cameras are commonly used within the Wisconsin Department of Natural Resources. With conventional film, it is highly unlikely that a negative can be manipulated without detection. The same cannot be said about images produced by digital cameras. The qualities that make digital images so desirable can result in challenges when digital images are used as legal evidence.
A photograph used as evidence must have relevance to the case and authenticity must be well documented. Authentication is a process of convincing a court that a photograph accurately depicts the scene at the time the photograph was taken. The authenticity of a photograph produced from film, i.e. negative or positive transparency, can usually be attested to by the photographer or other witnesses familiar with the scene at the time the photograph was taken.
Questions of authenticity can be quickly addressed by production of the negative for comparison with the photograph. If the photographer can truthfully state that the photograph accurately depicts the scene at the time the photograph was taken, it is highly likely that the photograph will be allowed into evidence.
The use of a digital image as evidence requires additional care because, unlike a negative, the original digital image can be easily manipulated. Images from digital cameras are stored on computer chips without film or paper. Digital images can be easily and quickly manipulated by virtually anyone who possesses a computer. Digital images can also be intentionally or unintentionally deleted or lost.
The terms enhancement and manipulation need to be defined. Enhancement in this document refers to the quality improvement of an entire digital image by making adjustments to contrast, brightness, focus, noise reduction and similar features. Manipulation refers to the changing of individual pixels that subsequently alters the actual scene. This goes beyond the simple act of improving the quality of the digital image. An example of digital image manipulation is changing the color or size of a hazardous substance discharge to surface water.
Any enhancement of a digital image should be done to a duplicate image and not to the original image. It is also suggested the actual enhancements to an image be recorded. Introduction of an enhanced duplicate image in a trial should be accompanied by introduction of the untouched original image for the purpose of comparison.
Many law enforcement agencies promptly download digital images to hard drives with the use of protective software programs or onto writeable compact disks (CDs). Writeable CDs use Write Once Read Many Times (WORM) technology. This ensures that the image once recorded onto the CD cannot be changed or deleted.
CDs have engraved unique serial numbers. The numbers can be used in the tracking of the image and will aid in verifying authenticity. Consideration should be given to storing images on writeable CDs.
In a court setting, an accurate and high quality print from the digital image will have to be presented. The quality of the print is dependent upon the quality of the digital camera and lens, image resolution, the capabilities of the printer, and the quality of the actual paper used to print the image. It is important to produce a print that is of the highest possible quality.
The use of digital images is still in its infancy in terms of evidence presentation. Failure to provide protection of the original image from the potential for manipulation, whether intentional or unintentional, could lead to the suspicion and subsequent challenges that the original image may have been tampered with. Proper care of images will refute these challenges.
Photographs can often be very powerful evidence. The integrity and authenticity of photographs should be maintained. Taking precautions to ensure proper handling of digital images will improve the likelihood that digital images will be admitted as evidence and given the appropriate weight.
With the use of digital cameras, it is important to follow the well established procedures that are recommended for cameras that use conventional film. However, because of the uniqueness of digital cameras, the following digital image management steps are recommended:
Digital Image Management
1. Be familiar with the operation of the assigned digital camera and digital imaging in general (many internet tutorials are available).
2. Digital camera ?field kits? should include the camera instruction manual, extra batteries and memory cards, e.g. CompactFlash, SmartMedia, etc., and a padded camera case.
3. As the image is taken with the digital camera, the digital image should be viewed through the camera?s LCD display to ensure that the image is of high quality and accurately depicts the scene. Continue to use this documentation procedure until the scene is accurately and completely documented.
4. Digital images should be promptly downloaded and viewed on a computer monitor to familiarize the photographer with the digital images and to ensure the digital images accurately depict the scene at the time it was photographed.
5. The original digital images should have a file name that includes the word ?original? or similar language, and should be preserved as evidence.
6. Any enhancements, including simple adjustments to brightness and contrast, should be made to a duplicate digital image and saved with a different file name. Manipulations must not be performed on any digital image that may be used as evidence.
7. An identical backup file of the images should also be made.
8. Consider using password protection, “write protect” features, or writeable CDs for storing digital images. Become familiar with writeable CD programs and use this technology if available at your office.
9. A brief report documenting how the digital images were handled, enhanced, and archived should be prepared and placed in the case file.
10. Staff routinely using digital cameras should continue to learn about the rapidly changing technology associated with digital cameras and images.
These recommendations are in addition to detailed recommendations for general evidence photography. For additional information on evidence photography and/or recommended internet tutorials on digital imaging, contact the author. Editing of this paper was performed by Rick Prosise, Stan Schneider and Steve Sisbach.
Questions or comments concerning this article are welcomed and can be directed to Dave Edwards, Wisconsin Department of Natural Resources, Office of Environmental Enforcement, 101 S. Webster St., Madison, WI 53707-7921, (608) 261-0779 or via email at ?david.edwards@dnr.state.wi.us?
Disclaimer
This document is intended solely as guidance and does not contain any mandatory requirements except where requirements found in statute or administrative rule are referenced. This guidance does not establish or affect legal rights or obligations and is not finally determinative of any of the issues addressed. This guidance does not create any rights enforceable by any party in litigation with the State of Wisconsin or the Department of Natural Resources. Any regulatory decisions made by the Department of Natural Resources in any matter addressed by this guidance will be made by applying the governing statutes and administrative rules to the relevant facts.