A Monochromatic Method for Measuring the Apparent Soil of Dyed Carpeting

Abstract

Reflectance methods have been investigated for measuring the ability of the fiber in dyed carpeting to retard or "hide" soil. The ideal method should be able to eliminate the effect of color which may mask or accentuate apparent soil. A method which approaches this ideal consists of measuring reflectance before and after soiling by using an interference filter with a bandpass centered at a wavelength close to the dominant wavelength of each color. This method reduces the effect of color sufficiently that the average calculated apparent soil for a set of 16 differently colored carpets soiled equally is significantly different from that of the same set of carpets after the addition of a small amount of soil (0.06% owf). Two other methods, one with a Y-tristimulus filter and another with three tristimulus filters (total color change), are not suitable for this type of evaluation.