Indigo pigment extraction

This summer I was experimenting with Indigo plants. Indigo is a very versatile plant, which grows the best in the summer in hot weather. It grows pretty big and wide so you have to leave a space between plants.

The plants are ready to harvest when 20” high and filled with pigment.

After collecting the leaves I placed them in a glass jar and fill with warm water covering the leaves completely, and adding some weight on top (like stones or bricks). When you see the water starting to turn blue color, “mermaid water”, then you will know that you are ready for the next step.

Remove the leaves (the smell is not pleasant) and add some pickling lime (calcium hydroxide). In the ratio of 1 tbsp on gallon mixed it together and aerate using two jars. You will see how water starts turning indigo blue, switch water from one container to another at least 20 times. And let it sit for a day.

The next day after the chemical reaction you will see the pigment separate from the liquid, as you see a dark substance on the bottom. Carefully remove as much as you can of yellow liquid without disturbing pigment.

Using a coffee filter, strain the rest of the liquid into another jar. And now you can collect your pigment in the jar and store it in a refrigerator or dry it and make it into a powder.

The wet pigment can be used for painting by adding to it soy milk.