The introduction of infrared sensitive digital cameras that can now detect bloodstains even when under layers of paint and is a use tool for solving crime may cause major changes to how crime is investigated. This is particularly valuable in locations where the perpetrators attempted to conceal evidence by covering bloodstains and other physical surface evidence with layers of paint., Digital cameras set to record detect infrared light can now detect bloodstains even when under layers of paint providing a new tool for solving old crimes. Even old bloodstains can harbor the DNA capable of identifying criminals and victims. . However, it must be detected first and those layers of paint can hide it from a visual inspection. But not from a digital infrared camera. Even without DNA bloodstains are valuable for identifying crime scenes. The splatter patterns also help law enforcement professionals reconstruct crimes and identify how the crime could have been enacted at a given location. Just the existence of human blood indicates that a crime was committed at a particular location. . . Because digital photography using infrared and ultraviolet is quick easy and inexpensive it will be affordable to more agencies and useful in more situations than previously. . “We hope it gives law enforcement the ability to go on hunches,” says Glenn Porter, an expert in forensic photography at the University of Western Sydney in Australia. .
Porter was formerly a forensic photographer with the Australian Federal Police. He sought out his former colleagues Farrah and Renshaw also with the Australian Federal Police. Together they tested infrared photography by photographing stains from diluted horse blood on primed plasterboard painted over with different types and colors of acrylic paint. They used a common digital camera to which they affixed an infrared light sensitive lens. The infrared camera detected the blood under six layers of black paint that was invisible to a standard camera under two layers of black paint along with other paint types and varying depths of paint layers. According to their report printed on 30 July 2012 in the Journal of Forensic Sciences this was effective with layers of purple, orange, blue, yellow and green.. Red paint was the east effective cover paint. White acrylic covered with three layers partly because the lead or titanium particles are good at scattering light according to Dan Kushel, a specialist in art conservation and imaging at Buffalo State University in New York. .
Monochromatic light like Polilight ™ is one of the tools to detect these stains. Blood reagents such as luminol can sometimes produce effects even after the blood is covered with layers of paint. Infrared light photography proved itself effective in both bloodstain detection and in art identification. . Infrared radiation penetrates visually opaque paint and material to reveal markings on underlying layers. This is successful in criminal and artistic forensics. .
Infrared and ultraviolet photography has been used forensically in the evaluation of documents and counterfeit currency. . It is a valuable tool in establishing the legitimacy of old master paintings. Art forensic experts used it to search for original sketches beneath the subsequent layers of paint. . Law enforcement also uses it to search for gunpowder residues, tissue abrasions, and evidence. It is not at all a new technique. What is new is the digital technology that makes it affordable enough for more agencies to put into play in more situations. Infrared film was difficult to handle, and expensive. Chuck McKern, an experienced IR expert, said “Itʼs difficult getting the film, difficult shooting with it, and difficult processing it.” .The new digital technology does not involve using the old film process so that eliminates the difficulties formerly associated with infrared forensic use. This makes it a candidate for primary crime scene investigation. This is especially valuable because infrared digital photography applies to a wide range of applications including document verification where it can identify obliterations falsifications and alterations. It is useful in scenes where there is a suspicion of violence where it is used for detecting gunpowder residue, the potential presence of blood as well as the splatter patterns and residues. It also can be used to investigate physical remains for deep tissue damage, scrapes bite marks and abrasions. In the case of burn victims, it can help detect tattoos, birthmarks and other personal identification indicators that would remain concealed to other investigatory methods.
It is clear to see how the new digital technology tested by Farrar, Porter and Renshaw can immediately help law enforcement departments in the United States and around the word with its comparative ease of use and much lower costs. These new advances and reports clearly show that infrared sensitive digital cameras can now detect bloodstains even when under layers of paint and is a use tool for solving closed case files. This is a easily portable solution to the old infrared film that was expensive, hard to use and difficult to carry. DNA recovered from old crime scenes may help exonerate persons wrongfully convicted, solve closed cases and convict perpetrators even when the evidence is hidden under paint. . The tests conducted by Porter and his former colleagues Farrar and Renshaw from the Australian Federal Police, nfrared photography techniques more accessible to a greater number of law enforcement agencies. Because this infrared digital photography is less complex, easily portable and more affordable it may become a common method to complement other law enforcement tools and methods. Monochromatic ultraviolet light and blood reagents such as luminol that sometimes produce effects after with blood covered with layers of paint and can then be used to further determine the presence of human blood after the infrared photography indicates a potential crime scene.
Once confined because of its cost to the investigation serious crime, documents and counterfeit currency along with costly evaluations to confirm the legitimacy of high priced art works such as old master paintings.. Infrared photography is now available to local law enforcement just as Porter envisioned when he set out with Farrah and Renshaw to develop this technique. Affordable digital infrared photographic technology can bring about almost revolutionary change in investigative practices as it replaces the difficult and expensive infrared film.
Works Cited
Daab, John. "Forensic Science and Fine Art Authentication: “La Bella." Art Forensics 04 10 2013: 1 - 9.
Ehrenberg, Rachel. "Camera hack can find crime scene." Science News 22 09 2012: 9.
Farrar, Andrew, Glenn Porter and Adrian Renshaw. "Detection of Latent Bloodstains Beneath Painted Surfaces Using Reflected Infrared Photography." (2012).
Schneider, Jason. "Forensic Imaging Goes Digital." Forensic Magazine 12 2006.
