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

NCJ Number
Forensic Chemistry Volume: 19 Dated: 2020
Date Published

This study determined the emissivity of nylon, cotton, polyester, and acrylic fabrics coated with dried rat blood in the thermographic infrared region (~8–12 µm wavelength) at 40 °C and at the lowest humidity researchers could attain 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 study’s 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 cm 2 of fabric. An acrylic fabric (ε = 0.82) shows an increase in emissivity of 0.05 under the same conditions. The research team 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 found that its emissivity increased from 0.90 at low humidity to nearly 0.94 at 90-percent humidity. 1 figure (publisher abstract modified)

Date Published: January 1, 2020