Forensic scientists will soon receive a new tool with a rich history: it hails from Ancient Egypt.
Recent studies have shown that Egyptian blue ink, created 5,250 years ago, can be used as a powder for fingerprinting where conventional tools fail.
Scientists became interested in the persistence of Egyptian blue, which still covers ancient sarcophagi and tomb walls, and found that this pigment emits near-spectrum infrared radiation under certain lighting conditions.
This property of paint can be useful for forensic purposes. Arriving at a crime scene, forensic experts usually apply a contrasting powder to objects with a brush, which adheres to the fingerprints left there. But prints are difficult to remove from glossy or embossed surfaces. In such cases, Egyptian blue can come in handy. The colorant is applied in the same way as a conventional powder, but then the surface is illuminated and photographed with a camera equipped with a filter that is sensitive to near infrared radiation. If there are prints, they will be clearly visible in the picture.