Linear density and maturity of cotton fibers have a considerable impact on yarn quality and processing performance in textile manufacturing. Sophisticated processing techniques require profound knowledge of raw material characteristics. The IIC-Shirley FMT dual-compression airflow method has been recognized and accepted as a rapid and accurate assessment of cotton fineness and maturity, far more so in the rest of the world than in the United States.

Air permeability measurements on fiber plugs are affected by the previous history of mechanical treatment of the cotton, i.e. raw cotton, card feed, slivers, laps or roving. Multivariate regression analysis applied to data generated by an FMT II laboratory instrument resulted in a set of equations that eliminates bias in measurements of fineness and maturity for cottons sampled from various stages in mill processing. This approach can generally serve to reduce the influence of specimen characteristics on airflow measurements.