This specially formulated indigo is already 60% reduced, therefore, it allows you to use Soda Ash instead of nasty Lye in the dye vat. Extremely easy to use, Pre-Reduced Indigo makes setting up an Indigo vat almost effortless. There is no need to grind, then paste up the Indigo granules because they dissolve easily in water. You can have the vat prepared in about 10 minutes!
Precautions: Please use an organic fume respirator when working with the Thiourea Dioxide (AKA Dyehouse Color Remover aka Thiox) or Sodium Hydrosulfite. Do not use utensils or dishes used for eating. Wear gloves. Always work in a well ventilated area.
When using bulk pre-reduced Indigo, the following recipe provided to us by the manufacturer fits well in a 5 gallon bucket:
- 50 grams Pre-Reduced Indigo
- 160 grams Thiourea Dioxide or Sodium Hydrosulfite
- 240 grams Soda Ash
- 15,000 ml water (15 liters)
When using the 3/4 oz packet, and if you don't have a gram scale or don't like doing conversions:
- 3/4 oz Pre-Reduced Indigo
- 2.3 oz Thiourea Dioxide or Sodium Hydrosulfite
- 3.5 oz Soda Ash
- 2 - 3 gallons water depending on how concentrated you want it or how big your pieces are
Make a vat with cool tap water, about 60 to 70 degrees Fahrenheit. A cylinder shaped container with a tight fitting lid works the best. Add the Indigo and the Thiourea Dioxide or Sodium Hydrosulfite to the vat and stir.
Try to dissolve the Soda Ash by adding a little boiling water to it. It won’t completely dissolve. Add the soda ash to the vat. With a dowel or stirring stick, stir in a circle, going in one direction. Slow down and reverse the direction of the stirring, dragging your stir stick along the outer edge of the vat before removing your stir stick. This will bring the foam that has formed, which is called the “flower”, to the center. Let the mixture settle. The liquid should be a clear yellowish-green color.
When you are ready to dye, wet your fabric and squeeze out any excess water. Skim the “flower” and crust off the top of the vat and set aside. Enter your wetted-out fabric slowly and manipulate under the surface of the water. You don’t want to stir up the sediment at the bottom of the vat. Nicely, you get way less with this product than with natural indigo. Squeeze the fabric as you lift it out trying not to drip or make bubbles, as this introduces more oxygen into the vat. When you lift your fabric out, it will be a yellow-green color. As the air hits the fabric, the indigo will gradually oxidize and the fabric will turn blue. After 15 to 20 minutes, you can re-dip your fabric for darker shades, or rinse and un-tie (if doing tie-dye) and wash.
When you are finished dyeing, put back the “flower” and stir the vat in the same circular manner as described above. Put a lid on the vat and it will be ready for another dye session when you need it. The indigo vat can last for several weeks or months if properly tended.
Tending an Indigo Vat:
An indigo vat can have a very long life if used and tended to regularly. As mentioned above, the best type of container for a vat is a cylinder shape with a tight fitting lid. This will give you room to dye the fabric without it touching the bottom and minimize the surface area that is in contact with air. Occasionally, you may need to add more of the reducing chemicals and the Pre-Reduced Indigo to keep the vat going. Always try to dissolve the Soda Ash in a little water before adding to the vat. Start by adding a little at a time. Sometimes more than one addition is needed. When you add something to the vat, it is important to wait for the chemical reaction to take place (at least 1 hour) before adding more.
- If the vat looks more blue-green than yellow-green, or if you see blue particles suspended in the liquid, the vat needs to be reduced more. Add 2 to 10 grams of Thiourea Dioxide or Sodium Hydrosulfite at a time.
- If the color seems weak, or the liquid in the vat is gray and watery, an addition of the Pre-Reduced Indigo is needed. Add 2 to 10 grams at a time.