To compare the color and composition of fabric samples.

Use pieces of cotton/polyester fabric of similar color but different composition. Fabric samples should be torn from the stock fabric so that fraying and stretching are evident. Size samples so they are just large enough to fill the sample holders. Pieces of fabric evidence should be stored separately in labeled, sealed bags. Assign small pieces to the crime scene and the suspects.

Provide students with three or four fabric samples with known percentages of cotton and polyester covering the range from about 40% polyester to 100% polyester.

Standard Reference Material

Visible, diffuse reflectance spectrophotometry (color)

Fourier Transform Raman spectrophotometery (composition)

Visible spectrophotometer with diffuse reflectance accessory ; FT-Raman spectrophotometer

For instructor (detailed); For student (brief)

Diffuse reflectance visible spectra of pink & green fabrics

FT-Raman spectra of pink & green fabrics

FT-Infrared with ATR accessory (composition)

Procedure