This most commonly describes the services provided by a physical science unit of a crime laboratory where the techniques of chemistry, physics, and geology are brought to bear on the identification of crime scene evidence. Such personnel are usually called criminalists and perform a variety of tests as well as use analytical instruments on trace evidence such as soil, paint, and glass. Generally not acceptable in most courts of law, and frequently challenged even if used for victim memory refreshment where it is allowed. An interesting field based on some of the same principles as interrogation in police work. The phrase used to describe a variety of techniques all involving study of a specimen under a microscope.
Evidence is collected using a micro-vacuum like the kind that clean computer keyboard keys.
The expertise is called forensic physical science, general forensic science, evidence collection, or criminalistics. Holds the promise of detecting other things over a longer time period. Part of the detective craft has always been to tell a story about the crime using pictures, and crime scene photography has always had its own standards over and above what the court requires. Digital photography needs to have similar standards because photographs can be easily retouched by computers. If a photography unit exists in a crime lab, this unit usually helps prepare courtroom exhibits.