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Just Science: 2019 NIJ R&D: Just Skin Deep

NCJ Number
Katherine Scafide; Daniel Sheridan
Date Published
May 2019
1 page

This first episode of the 2019 R&D season of the National Institute of Justice's (NIJ's) Just Science podcast series consists of an interview with Dr. Katherine Scafide and Dr. Daniel Sheridan about their use of alternative light sources (ALSs) for the detection and assessment of cutaneous bruising.


Until the 1990s, it was commonly believed that clinicians and forensic professionals could estimate a bruise's age by analyzing its color change; however, research has shown this is not the case. Seafide and Sheridan are conducting a project focused on creating a method for accurately assessing bruises by using various filters to isolate wavelengths of light. In the current interview, they discuss the characteristics of bruising, the factors that affect bruise perception, and their use of paintballs. The overall purpose of the research discussed in the interview is to determine whether or what scientific facts can be determined from an examination of bruises under various ALSs. Bruises are noted to be potentially important evidence in criminal cases that focus on the nature, cause, and time frame for an injury. Scafide and Sheridan state that there is little scientific basis for establishing whether an injury is a bruise or a contusion, as well as the cause or force that produced the bruise. In addition, there are numerous variables that may impact the cause, color, and shape of a bruise in a particular person, such as age, gender, skin color, and medicines consumed. The research reported here is being conducted with volunteers whose physical and medical features are documented and whose bruises are known to be caused by propelled paintballs. The features of the bruises are regularly checked under various ALSs to determine which types of ALS perform best for observations of subjects with particular skin color and other variables.