Questions
1. What is meant by friction?
2. What is meant by the expression “fastness of color of two fabrics”?
3. How may the fastness of a colored material be tested to withstand friction?
Experiment 39—Test of Fastness of Color against Rain
Apparatus: Water, undyed yarn.
Materials: Silk and woolen fabrics.
Reference: Textiles, page [243].
Directions
Silk and woolen materials for umbrella making, raincoats, etc., are expected to be rainproof. These fabrics are tested by plaiting with undyed yarns and left to stand all night in water. Notice whether the color of the fabric has run into the undyed yarns.
Take a sample of the fabric and shake some drops of water on it. Notice whether it loses its luster when the drops have dried. Spotting may be prevented by placing a damp cloth on the wrong side of the material; roll the two together, and when evenly damp, unroll and press through the damp cloth with a fairly hot iron.
Place a piece of the fabric in the sun so that the sun and rain may come in contact with it. Notice whether it loses its color and becomes gray and dull.