on toolmark matches (including legal testimony) should be supported by the work that was done in the laboratory, by the notes and documentation made by examiners, and by proficiency testing or established error rates for individual examiners in the field and in that particular laboratory, but should not overreach to make extreme probability statements.
In the next several chapters, we explore the current state of ballistic imaging technology. As context for this discussion, we note that imaging and photography have a long and somewhat controversial history in traditional firearms identification.
Moran (2003) summarizes some of the historical debate over the use of comparison photographs, culling relevant quotations from source materials. Some of the pioneers of the field of firearms identification—Goddard, Burrard, and Hatcher—considered photography to be valuable, if not essential, Burrard going so far as to comment that “any evidence unsupported by photographs cannot be regarded as being anything more than an expression of opinion. Photographs are, accordingly, essential; and such as are deemed necessary must be taken through the microscope” (Moran, 2003:175). However, Hatcher sounded a note of concern: “There is a difference in the ability of the various experts to use the microscope and camera, so that in the hands of a very skilled operator they may show the correspondence or lack of correspondence very clearly, while in the hands of a poor or mediocre operator, they may show the same thing faintly, or may even fail to show them at all” (Moran, 2003:176). However, with the passage of time, the practice of using photographs to document identifications fell out of favor, so much so that a 1957 revision of Hatcher’s 1935 text now stipulated that “photo micrographs are now rarely used,” for a variety of reasons (Moran, 2003:177):
Courts tended to accept examiners’ testimony on identifications without the “visual proof,” obviating the need to prepare the photographs.
Preparation of the photographs took time, time that laboratories were unwilling to commit due to increased caseloads.
Static views of an evidence match were deemed unsatisfactory, relative to the full range of panning and rotation possible during direct manipulation of the evidence.
“These pictures were not understood by juries,” and “a good deal of knowledge and experience are necessary to evaluate them.”
“Some men after years of working in Firearms Identification refuse to make a positive identification from pictures alone.”