Modeling the Dependence of Fabric Reflectance on Denier per Filament

A ray trace model for predicting fiber optical properties has been previously described. This model, which treats each filament in a yarn bundle independently, has been extended to include multifilament scattering. The new model is used to predict the reflectance properties of a series of simulated yarn bundles with different numbers of filaments, providing further insight into the interaction of light with a fabric. Two effects of reducing denier per filament are predicted: decreased dye yield and increased back-scattering. The dye yield data are in agreement with the empirical relationship that the amount of dye required to achieve a given depth of shade varies as the inverse square root of the denier per filament.