Indigo, Organic Vs Chemical

Indigo dying is a long tradition in Japan and has been used for centuries. But a lot has changed over the years and the majority of products and garments are now chemically dyed.

Whilst in Kyoto, Japan I stopped by Aizenkobo workshop which has been running for three generations, to check out and learn more about the organic dying process and what the pros/cons are of both.


Organic indigo can be extracted from the fiber of several different plants. In Japan, the only useable indigo plant is polygonum, which is well-known for its outstanding deep color.

Fermented polygonum, the dye pigment, is called "sukumo."

In addition to the "sukumo," wheat husk powder, limestone powder, lye ash, and sake are also mixed into the vats to complete the liquid dye.

Then for approximately a week, the dye naturally begins to ferment until it reaches its usable state.

Fabrics and materials, specifically cotton and linen are generally soaked and dried 15 to 20 times.

Silk, on the other hand, must be soaked and dried 40 to 45 times. This is the only way to deepen the color.

The dyed thread and materials are sun-dried, which is when the deep indigo blue appears most strongly on the fiber surface.

Indigo also strengthens the material. Indigo dyeing is considered one of the most beautiful dyeing techniques known to man.

Dyed materials soften with use, and the quality of the color's richness increases with time.


The chemical process can be bought from hobby stores or over the internet, I personally go mine from an store.

In the pack you will get the following;

  • 10 grams indigo dye

  • 20 grams soda ash

  • 15 grams Spectralite (thiourea dioxide or thiox)

    or 30 grams of Dithionite (sodium dithionite or sodium hydrosulfite)

  • 5 liters water at 45°C

  • 1 kg fiber (yarns, fabric, etc)

The process of creating your indigo vat takes around 1.5 hours in total, depending on how big it is. Then the materials you want to dye are placed into the vat for 20mins, then taken out to oxidize in the sun for a further 15mins.

You will notice that your vat is green and so is the dyed products, once the air hits them you can watch them turn blue.

After about 24hrs of drying you can wash the products in a normal washing machine, it is said to add a little vinegar to help get an even format in the dying.

With chemical, unlike organic, the dye will fade over time.