Camouflage of cotton fabrics in visible and NIR region using three selected vat dyes
Level 5 - mechanism / opinion, no new human data
Level 5 by design analogy; laboratory bench experiment on material optical properties.
OpenAlex W2090505874 · doi:10.1002/col.21778
What was done
Cotton fabrics were dyed with three vat dyes (C.I. Vat Blue 6, C.I. Vat Yellow 2, and C.I. Vat Red 13) both individually and in mixtures to mimic the reflectance profiles of two types of fresh green leaves. Transmittance curves of dyes in acetone and reflectance curves of dyed fabrics in visible and near-infrared (NIR) ranges were measured. Chromatic values (CIE1976 L*, a*, and b*) were determined to compare against 1948 US Army standard shades (NATO green and forest green), and durability was evaluated following washing and light exposure.
What was found
C.I. Vat Blue 6 showed the greatest reflectance similarity to green leaves at concentrations of 0.85% and 1.2% on weight of fiber (owf) compared to the other two dyes. Mixtures produced NATO green and forest green shades on cotton with color differences of ΔECMC < 2, falling within the reflectance range of the reference green leaves. Colorfastness properties were reported as good, with minimal impact on visible and NIR camouflage properties after washing and light exposure.
Why it matters
This study demonstrates that specific vat dye formulations on cotton can replicate natural foliage reflectance in the NIR spectrum while meeting visible-spectrum military color specifications.
Limits
Bench-scale materials testing with no operational field trials. The comparison used only two types of green leaves as natural references, and the abstract omits quantitative reflectance percentages and standardized fastness test ratings.
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