Scanning Microscopy


Examination of fabrics to determine if they have been cut or torn may become an important issue in criminal investigations under a variety of circumstances. Since most fabrics are composed of extremely fine fibers, they present a difficult problem when such examinations are conducted by stereo light microscopy. This is particularly true when the cut fabric yarns are grossly displaced or disturbed from their original positions and where fabric edge characteristics lack the observable specificity to provide any definitive conclusion. The scanning electron microscope, due to its higher magnification, resolution and depth of field, provides an excellent technique for examination and differentiation of cut and torn fabrics. The acts of cutting and tearing produce different morphological characteristics on the separated fiber ends. Examination of these fiber ends at significantly high magnification and comparison with deliberately produced cut and torn fabrics will allow positive identification of cuts and tears. Three actual criminal cases involving man-made and/or natural fibers in woven and/or nonwoven fabrics demonstrate the usefulness of the technique where visual and stereo light microscopical examinations were inconclusive.

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