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A study of the mid-infrared emissivity of dried blood on fabrics

NCJ Number
Forensic Chemistry Volume: 19 Dated: 2020
Raymond G. Belliveau; et al
Date Published

In this project, the emissivity of nylon, cotton, polyester, and acrylic fabrics coated with dried rat blood were determined in the thermographic infrared region (~8–12 µm wavelength) at 40 °C and at the lowest humidity that could be attained in the laboratory.


Results show the emissivity of known nylon (ε = 0.87), cotton (ε = 0.88) and polyester (ε = 0.88) fabrics in the authors’ laboratory increased by 0.01, 0.01 and 0.03 respectively when coated with dried blood at a concentration of 100 µL of whole blood per 0.9 cm2 of fabric. An acrylic fabric (ε = 0.82) showed an increase in emissivity of 0.05 under the same conditions. The researchers also investigated the change in emissivity of an acrylic fabric sample coated heavily with whole rat blood 8 years previously as a function of humidity, and its emissivity increased from 0.90 at low humidity to nearly 0.94 at 90 percent humidity. (publisher abstract modified)

Date Published: January 1, 2020