NCJ Number
35749
Journal
Police Chief Volume: 42 Issue: 10 Dated: (OCTOBER 1975) Pages: 34 & 39-40
Date Published
1975
Length
3 pages
Annotation
A DESCRIPTION OF THE PROCESS OF ELECTRON-EMISSION RADIOGRAPHY, A PROCESS WHICH IS SAID TO ENABLE THE INVESTIGATOR TO LIFT FINGERPRINTS FROM CLOTHING, FREQUENTLY HANDLED DOCUMENTS, AND SKIN.
Abstract
THE AREA TO BE COVERED IS DUSTED WITH LEAD POWDER, WHICH ADHERES TO THE PRINT, AND COVERED WITH A SHEET OF X-RAY FILM. FILTERED X-RAYS ARE DIRECTED THROUGH THE FILM, ONTO THE PRINT, CAUSING THE LEAD POWDER TO EMIT PHOTOELECTRONS WHICH LEAVE AN IMAGE ON THE FILM. BECAUSE THE FILM IS MORE SENSITIVE TO PHOTOELECTRONS THAN TO THE FILTERED X-RAYS, THE IMAGE SHOWS ONLY THE LEAD POWDER WITHOUT INTERFERING BACKGROUND IMAGES.