Directions
1. Prepare a solution of coloring matter by dissolving a half ounce of logwood in a quart of water. Filter the solution. Place a piece of silk skein, from Experiment [22], in the liquid and boil ten minutes. Then wash the dyed silk and notice whether the dyestuff washes off or not.
2. Repeat the same experiment using the same weight of silk yarn without weighing it. Compare the results.
Experiment 24—Test to Distinguish Piece-Dyed from Yarn-Dyed Fabric
Apparatus: Pen knife.
Materials: Woolen and cotton fabrics.
Reference: Textiles, pages [66-68].
Directions
Unravel threads of the suspected sample, and with a blade of pen knife note whether the dyestuff has penetrated through the yarn as noted by the depth of color in the interior of the yarn. In case there is the same depth of color in the interior as on the surface, the fabric is yarn-dyed. If on the other hand, the interior of the yarn is not so highly colored as the exterior, it is piece-dyed.
Questions
1. What is meant by yarn-dyed fabric?
2. What is meant by piece-dyed fabric?