1. Prepare a solution of coloring matter by dissolving a half ounce of diamond dye (green or red) in a quart of water. Filter the solution. Place a piece of white woolen cloth in the liquid and boil ten minutes. Then wash the dyed fabric and notice whether the dyestuff washes off or not.
2. Repeat the experiment, using the same weight of undyed woolen yarn. Repeat with worsted yarn.
3. Repeat the experiment using the same weight of wool sliver.
4. Notice which has the deeper color. The degree of color depends on the amount of twist in yarn. Which sample has absorbed the greatest amount of dyestuff from the liquid?
a. Why is a yarn-dyed fabric faster than a piece-dyed?
b. Why is a raw stock dyed fabric better than piece or yarn dyed?
Experiment 21—Dyeing Cotton
Apparatus: Porcelain dish, filter stand, etc.
Material: Piece of cotton cloth.
Reference: Textiles, page [67].
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 cotton cloth in the liquid and boil ten minutes. Then wash the dyed fabric and notice whether the dyestuff washes off or not.