Electrostatic detection device
（重定向自Electrostatic Detection Apparatus）
An electrostatic detection device, or EDD, is a specialized piece of equipment commonly used in questioned document examination to reveal indentations or impressions in paper which may otherwise go unnoticed. It is a non-destructive technique (will not damage the evidence in question) thus allowing further tests to be carried out. It is a sensitive technique capable of detecting indentations on pages several layers below the top sheet, and many years after the indentations were created.