Mordanting:

The first step of the actual dyeing process is mordanting. A mordant is a chemical that, when "cooked" with the fiber, attaches itself to the fiber molecules. The dye molecule, then, attaches itself to the mordant. Different mordants give different colors when combined with the same dye. For example: the dye, cochineal when used with alum sulfate gives a fuchsia color; when used with tin, the color is more scarlet, and when used with copper, it is purplish. Mordants except for alum and iron, are considered toxic and therefore self defeating. The mordants are toxic to the dyer and the disposal of the bath becomes an environmental problem. Therefore the choice of mordants is limited. Alum compounds and iron are ideal safe mordants. Treating cotton with Tannic acid is useful as it prepares the fabric for effective absorption of the dye.

With protein fibers (wool, mohair, alpaca, angora–animal fibers) alum sulfate is recommended. To mordant, use 10% of the weight of fiber (WOF). Dissolve the alum with boiling water and add this to the dye pot. Use enough water in the pot to amply cover the fiber. Bring the temperature up to 180-190 degrees F. for most protein fibers over ½ hour. Hold at temp for another ½ hour. Let the pot cool for several hours or overnight. The fiber will continue to absorb the mordant as it cools. Squeeze out the excess water, but do not rinse the fiber.

The Process:

• Weigh fabric (WOF).
  
• Wash fabric if unsure about sizing.
  
• Measure water into pot (25 times WOF).
  
• Measure a wetting agent.(4% WOF).
  
• Add the wetting agent to the pot.
  
• Add damp fabric.
  
• Heat slowly, allowing ten minutes to reach 120°. This is called the "wetting out" process.
  
• Weigh out mordant (I7% WOF).
  
• Weigh out more water (3 times weight of mordant) into a separate container. Add mordant slowly. If you add it too quickly it will bubble up and spill over. Stir until completely dissolved.
  
• Add mordant to dye bath. Agitate fabric well and stir frequently while holding temperature at 120° for ten minutes.
  
• Raise dye bath temperature to 180° over a period of ten minutes.
  
• Hold temperature at 180° for ten minutes, agitate often.
  
• Remove fabric.

Note: time periods mentioned can be extended based on mordants and dyes used.

Mordanting is followed by dyeing.

Dyeing

The Process:

WOF - Weight of fabric - All measurements are based on this amount.

Fabric - Natural fabrics (cellulose or protein) that has not been bleached. We have had good results with some rayons. If unsure whether or not your material has been sized, it should be washed before dyeing.

Water Ratio - 25 to 1 - A one pound dye lot will require twenty-five pounds of water, or twelve and one-half quarts.

• Weigh and mordant fabric
  
• Weigh out dye. Example: a pale peach will require a lower % of Rubia cordifolia than a dark orange.
  
• Put water into dye pot (use 25 times WOF).
  
• Dissolve dye in a small amount of water and add to dye bath.
  
• Place damp, pre-mordanted fabric in dye bath. Raise temperature to 120°, and hold for ten minutes, agitating frequently.
  
• Raise temperature to 180°, over a period of ten minutes and continue to stir.
  
• Hold temperature at 180° for ten minute
  
• Remove fabric. Rinse in cold water.
  
• Wash fabric in cold water.

Times periods for dyeing are flexible depending on fabric and dye used.

Post Dyeing Mordanting:

Sometimes mordanting is done post dyeing. This is in addition to the pre-dyeing mordanting. Tin and Vinegar are the common post-dyeing mordants used for “fixing” the dye.