Best Practices for Forensic Photographic Comparison
Scientific Working Group on Imaging Technology (SWGIT)
See also the instructional videos on "Crime Scene and Evidence Photography"
Objective
The objective of this document is to provide personnel with guidance regarding practices appropriate when performing photographic comparison as part of image analysis.
SWGIT Postion On Forensic Photographic Comparison
Photographic comparison is an intrinsic component of many scientific and technical disciplines. Such disciplines and industries include astronomy, geology, geography, medical specialties such as radiology and pathology, intelligence and surveillance, manufacturing quality assurance, and insurance. Forensic photographic comparison is recognized as scientifically valid within the forensic science community. The first publicly prominent Forensic Photographic Comparison examinations took place as part of the Warren Commission investigation into the assassination of President Kennedy. Photographic comparisons in this investigation were used to help establish the rifle as being Oswald’s as well as to establish that the “Backyard Photos” were taken with Oswald’s camera.
Introduction
Photographic Comparison is an assessment of the correspondence between features in images and known objects or images for the purpose of rendering an expert opinion regarding identification or elimination (as opposed to a demonstrative exhibit). Photographic Comparison is a subtask of Image Analysis, and general best practices issues are discussed in SWGIT document “Best Practices for Forensic Image Analysis”. This document addresses issues specific to Photographic Comparison.
Scope Of Forensic Photographic Comparison
Forensic Photographic Comparison examinations may be conducted on virtually any item, subject, or image. Practitioners of Forensic Photographic Comparisons in the field of Image Analysis should have expertise in image science, an understanding of the principles of individualization, and knowledge relevant to the specific subject under examination. Practitioners should be able to demonstrate sufficient knowledge of the subject matter to support their conclusions.
Several other forensic disciplines rely extensively upon photographic comparison techniques as a part of their procedures, such as footwear and tire impression analysis, latent print analysis, questioned document analysis, trace evidence analysis, and tool mark analysis. These subject matter experts use photographic comparison as a tool within the context of their domain expertise. This document is geared toward those comparison examinations typically performed by Image Analysis examiners outside the scope of these other disciplines.