Defense Date
2026
Document Type
Directed Research Project
Department
Forensic Science
First Advisor
Stephanie Walcott
Second Advisor
Stephen Stockman
Third Advisor
Curtis Marshall
Abstract
Tattooing, also known as stippling, is a phenomenon that occurs from excess gunpowder being discharged from a firearm into the skin, and presents as reddish-brown or orange lesions surrounding an entrance wound on the skin. Distance determination is a practice used in many forensic laboratories to establish possible ranges of distances between the muzzle of a firearm and a target, and stippling is commonly used for this comparison. Conclusions are made by comparing the unknown pattern to known distance patterns, and determining which one is most similar. In one case, a firearm was discharged at an unknown distance and there were differing opinions on the muzzle to target distance, and instead of stippling, soot was used for distance determination. This research aims to determine if soot or stippling is a more accurate way to determine distance. Blotter paper and pig skin were the materials used in this research, as blotter paper is commonly used in forensic laboratories and pig skin is an effective human skin simulant. There were a total of 44 samples obtained. Transparent overlays were used to mark stippling on the blotter paper and pig skin. Three overlay sets were produced for the pig skin: unwashed, the first time after washing, and the second time after washing. For stippling comparison, the overlays for the blotter paper and second washed pig skin were uploaded into the software ImageJ. The amount of stippling on blotter paper was found to decrease as distance increased, and the diameter of the stippling pattern was found to increase as distance increased. Similarly, the diameter of stippling on the pig skin samples was found to increase as distance increased. The quantity of stippling on the pig skin samples varied. Soot only appeared on contact samples for the pig skin but appeared up to 9 inches on the blotter paper samples. Overall, soot and quantity of stippling were found to be poor at estimating target to muzzle distance, but diameter of stippling was found to be an accurate and effective way to estimate target to muzzle distance.
Rights
© The Author(s)
Is Part Of
VCU Master of Science in Forensic Science Directed Research Projects
Date of Submission
7-9-2026