The effect of fluorescent whitening agent on hunter camouflage clothing

Fluorescent whitening agents (FWAs) are chemicals added to most fabrics and papers during manufacture to increase color temperature, whiteness , and brightness. FWAs accomplish this by absorbing energy in the ultraviolet (UV) part of the spectrum and emitting it as visible blue light. Recently, hunters have become concerned that FWA could be reducing the effectiveness of their camouflage clothing. As a result, some manufactures have begin making their camouflage clothing (camo) without FWA, and a spray-on product has been introduced to block the action of FWA. Radiometric spectra recorded from 300 to 500 nm under full sun and deep shade conditions suggest, however, that these concerns might not be fully justified. In fact, the FWA made some camouflage cloth samples a better match to the spectra of natural foliage in the UV portion of the spectrum, and the use of a spray to block the action of the FWA reduced the match of some camouflage samples to the foliage in portions of the visible blue spectrum (400-500 nm)