【国外标准】 Standard Guide for Microscopical Examination of Textile Fibers

4.1 Microscopical examination is generally a non-destructive, rapid, and reproducible means of determining the microscopic characteristics, optical properties, and generic polymer type of textile fibers.4.2 Side-by-side microscopical comparisons provide a highly discriminating and efficient method of determining if two or more fibers can be differentiated.4.3 This guideline requires specific pieces of instrumentation outlined herein.1.1 This standard covers guidelines for microscopical examinations employed in forensic fiber classification, identification, and comparison. The microscopical examination of fibers includes the use of a variety of light microscopes, such as stereomicroscopes, compound microscopes, and comparison microscopes, as well as a variety of illumination types, such as bright field, polarized light, fluorescence, and interference. In certain instances, the scanning electron microscope can yield additional information. The particular test(s) or techniques employed by each examiner or laboratory will depend upon available equipment, examiner training, and the nature and extent of the fiber evidence.1.2 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.1.3 This standard is intended for use by competent forensic science practitioners with the requisite formal education, discipline-specific training (see Practice E2917), and demonstrated proficiency to perform forensic casework.1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.1.5 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.