Latent Print Development - National Criminal Justice Reference ...

CHAPTER 7
LATENT PRINT
DEVELOPMENT
Brian Yamashita and
Mike French
Contributing authors
Stephen Bleay,
Antonio Cantu, Vici Inlow,
Robert Ramotowski,
Vaughn Sears, and
Melissa Wakefield
7.1 Introduction
Latent fingerprint development may be achieved with a
wide array of optical, physical, and chemical processes,
most having evolved during the past century. Because
some techniques are often intricately related and continuously
changing, it is imperative that those involved in
laboratory and crime scene processing are well trained and
well practiced (Trozzi et al., 2000, pp 4–9; Kent, 1998).
For those involved in crime scene and laboratory work,
safety is paramount. It is important to follow safe work
practices when using the processes described in this chapter.
This can be accomplished by observing manufacturer
warnings, reading material safety data sheets, and observing
one’s own institutional policies regarding evidence
handling and fingerprint development. It is also important
for those working with potentially hazardous materials
or equipment to wear the appropriate personal protective
equipment, such as gloves, lab coats, eye protection,
and respirators; to use engineering controls such as fume
hoods; and to practice proper laboratory procedures to
reduce exposure to pathogens or harmful chemicals
(Masters, 2002).
7.1.1 Types of Prints
Latent Print Development C H A P T E R 7
Fingerprints found at crime scenes or developed in the
laboratory are categorized by some examiners as patent,
latent, or plastic impressions (Lee and Gaennslen, 2001,
p 106), although all three types are routinely associated
with the term latent print.
A patent print is simply a visible print. Many of these types
of prints are wholly visible to the unaided eye, and only
some form of imaging is needed for preservation. A good
example of a patent print would be a greasy impression left
on a windowpane. Patent prints can also be left in blood,
paint, ink, mud, or dust. Lighting is a very important consideration
in the search for this type of fingerprint; a good
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