Evidence Technician Exam

A negative imprint is created when footwear or tires lift off dry residue from a surface. This type of imprint occurs when an object, such as a shoe or tire, makes contact with a surface containing a particulate material (like dirt, dust, or sand) and then lifts away, leaving behind the impression of the object's contours in the residue that remained attached to the surface. The area around the impression is where the residue was disturbed or removed, resulting in a negative space that mirrors the shape of the shoe or tire. This negative imprint can be crucial evidence at a crime scene, allowing investigators to analyze the tread patterns and characteristics of the footwear or tire that left the mark.

In contrast, a positive imprint would involve a direct transfer of material from the shoe or tire to the surface, creating an impression with the material itself, rather than lifting the residue. Other options such as wet origin and contaminated do not pertain to the specific characteristics of imprints caused by lifting residue and therefore are less relevant in this context.