Trace Evidence Examination

Forensic Evidence Examination

Microspectrophotometers are used for trace evidence examination to compare fibers, paints, soils, glass, plastic and questioned documents..

 

 

 

Forensic evidence is analyzed with a microspectrophotometer

UV-visible-NIR absorbance spectra of three single textile fibers.

 

 

Microspectrophotometers are used to examine microscopic amounts of trace evidence.

Trace evidence examination is the field of forensic science that relates to the examination of microscopic amounts of evidence.  This field covers everything from textile fibers, glass and plastic fragments, paint chips and smears, soils and much more.  One of the most common tasks of the forensic scientist is to determine if a known and a questioned sample are the same.  Another, but more difficult task, is to determine the source of an unknown sample.  Often tests are done by comparison with other original samples or by comparison with standard reference materials.

Many types of tests can be performed by the forensic scientist on trace evidence.  Many of these tests are determined by the type of evidence that is being examined.  Due to the microscopic nature of most trace evidence, microspectrophotometers such as the 20/30 PV™ are commonly found in forensic laboratories.  This system is able to provide both images and spectra of microscopic features of any type of trace evidence in the ultraviolet, visible and near infrared regions.  The visible part of the spectrum is important as it helps distinguish between different colors found in trace evidence.  The UV is important as many of the colorants used also have a UV active component.  The NIR region is important as there may be important sample variations observed here.  A 20/30 PV™ will allow the forensic scientist to take both images and microspectra™ in UV, color and NIR.

Learn more about forensic analysis:

What is a Microspectrophotometer?

Dyed hairs and Textile Fibers

Paint Evidence

Questioned Documents

Glass Refractive Index

UV-visible-NIR Microspectrophotometers

Raman Microspectrometers