Scale Heights of Chemically Treated Wool and Hair Fibers

The document reports on a study examining the effects of chemical treatments on the scale heights of cashmere fibers, which are often used for fiber identification. The study found that chemical treatments, such as those used in commercial processing for carbonizing and bleaching wool and cashmere fibers, can raise the scale edges above the main body of the fiber before they are completely etched away. This effect was demonstrated through a specific example where a cashmere fiber treated with 37.5% HCl acid and 3% hydrogen peroxide showed a scale height exceeding 0.5 µm, which is typically considered the threshold for distinguishing wool from cashmere. The study suggests that fiber identification based on scale heights may be misleading for chemically treated fibers, as the treatments can significantly alter the scale heights. The findings are supported by other published research, indicating that the underbody of the scale is more accessible to chemical penetration than the main body. The study concludes that caution should be exercised when applying statistics for scale heights of untreated fibers to chemically treated fibers.