What are the three primary types of impression evidence?

The three primary types of impression evidence are imprints, indentations, and striations. Each of these types plays a crucial role in forensic investigations.

Imprints refer to two-dimensional impressions left on a surface by an object. This can occur when an item, such as a shoe or tire, makes contact with a softer surface like mud or sand, leaving a recognizable pattern that can be directly compared against known sources.

Indentations are three-dimensional impressions that occur when an object presses into a softer medium, such as a shoeprint in snow or compressed soil. These impressions capture details of the object's shape and structure, which can aid in identification.

Striations are linear marks found on surfaces caused by sliding or scraping actions, often seen in tool marks or firearm evidence. These markings result from the interaction between surfaces and provide critical information about the movement and force applied.

Understanding these categories is essential for evidence technicians, as they provide vital details needed for connecting suspects to crime scenes or specific actions, making them integral to investigations.