How to Prepare an Indigo Dye
Indigo is a natural, plant-based dye that imparts a deep blue or purple color. By preparing the indigo with other chemicals, you can create your own natural indigo dye in which you can color garments. The project is appropriate for supervised students and is fitting in lessons about ancient times, clothing production or basic chemical reactions. Whether you are engaging in the process for educational or artistic reasons, preparing an indigo dye is a precise but straightforward task.
Things You'll Need
- Newspapers
- Smock or old clothing
- Latex gloves
- Chemical
- 4-gallon vat
- 2, 4-cup mixing containers (that can handle harsh chemicals)
- 3 tbsp. indigo grains
- 1 cup lukewarm water
- Stirring spoons (wooden or plastic)
- 1 1/2 cups cold water
- 5 tsp. lye
- 3 gallons and 1/2 cup warm water
- 1 1/2 tsp. Thiox
- 1 tsp. Metaphos
- 1/4 cup salt
Instructions
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1
Cover your work area with newspapers. Work outdoors, if possible. Wear smocks or old clothing while you work. Put on latex gloves and a chemical mask before you begin mixing.
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2
Pour 3 tbsp. of indigo grains into the 4-gallon vat. Pour lukewarm water into the vat. Stir the mixture with a spoon as you add the water. Stop adding water when the mixture becomes a lump-free paste. Set the vat aside.
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3
Pour 1 1/2 cups of cold water into one of the 4-cup mixing containers. Add 5 tsp. of lye to the water. Set the container aside.
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4
Pour 1/2 cup of warm water into the other 4-cup container. Add 1 tsp. of Thiox. Mix the ingredients with a spoon. Set the container aside.
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5
Pour the lye mixture slowly into the vat with the indigo paste. Stir the mixture gently with a spoon.
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6
Pour the Thiox solution into the vat. Stir the solution gently. Avoid lifting the spoon out of the mixture as you stir.
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7
Allow the solution to reduce for about 30 minutes to one hour. Stir the solution gently while it reduces. Precise reduction times vary by temperature and quantity. The process is complete when the dye turns yellow.
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8
Pour 3 gallons of warm water into the second vat.
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9
Add one teaspoon of Metaphos and 1/4 cup of salt. Stir the mixture.
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10
Dissolve 1/2 teaspoon of Thiox in warm water. Pour the mixture into the vat.
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11
Add the yellow, reduced contents of the first vat to the second. Pour the mixture as slowly as possible. Stir the new solution gently.
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12
Allow the solution to reduce for thirty minutes to one hour. The solution should be translucent with a yellow-green tint. The surface of the mixture should look dark blue and metallic. Give the solution more time to reduce, if it does not have these qualities.
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Tips & Warnings
Exercise extreme caution when working with chemicals. Cover your hands, mouth, eyes, skin and clothing as you make the mixture. While finished indigo dye is safe for younger children (ages 6 to 11) to use, they should only observe the dye-mixing process. Older students (ages 12 and up) may aid in the mixing process or observe.
