Cotton Fiber

Transmitted Cross Polarized Light Illumination

The apparent twist in these fibers is typical of cotton. A unique optical property of cotton is its
lack of an extinction position. As the stag is rotated between crossed linear polarizing filters
the fiber's brightness doesn't change. Cotton is a very common clothing and bedding fiber. It is very common in bedroom samples and in hospital
environments. It is also the main fiber in common shop rags. When cotton is mercerized the twist is
greatly reduced and the fiber darkens significantly on rotation between crossed linear polarizers.