Forensic Fiber Analysis: Advanced Microscopy and Microchemistry (1507)




Prerequisite: course 1201 or equivalent.


Day 1:

*Introduction and overview of forensic fiber microscopy, historical background.


*Morphology I: The structure of fibers in longitudinal view. The utilization of stains for chemical identification, contrast and demonstration and mapping of additives and structures.

*Morphology II: The shape and structure of fiber cross-sections. Interpretation of cross-sections. Modification ratio. Techniques for the preparation of cross-sections. Correlation of longitudinal appearance and cross-section and determination of denier from single fibers.

Day 2:

*The identification of vegetable fibers: Concept of the technical fiber and fiber ultimates. Scientific and common names and the importance of authentic reference material. Origin of the non-woody vegetable fibers in the plant stem. Diagnostic tissues and cells. Crystals. Maceration techniques. Optical crystallographic characteristics. Stains.

Day 3:

*Optical Properties I: The color of fibers. Normal dyeing, solution dyeing and novel dyestuffs. Dichroism and dyeing theory. Fluorescence. Characterization and comparison of color in fibers from the forensic perspective.

*Optical Properties II: Refractive indices, birefringence and sign of elongation their determination, origin, and interpretation. The use and misuse of compensators. The Standort Diagram.

Day 4:

*Optical Properties II (continued): Techniques for the determination of the principle optical properties of fibers and their use in the identification and comparison of synthetic and regenerated fibers. Fiber determinations.

*Thermal microscopy: The thermal behavior of thermoplastic fibers and its use in identification and comparison. Technique for determining the melting range of fibers with the microscope hot stage.

Day 5:

*Microchemical Methods: The value of chemical and elemental information in forensic fiber examinations. Chemical information from infrared spectra. Elemental information form x-ray spectroscopy. Classical microchemical techniques. Techniques for performing microchemical tests on microscopic lengths of fibers. Criteria for fiber comparisons and the interpretation of results.
