Japanese Indigo


English translation

At Litmus, we produce indigo dye using a very old coloring technique passed on from centuries ago in Japan. “Aizome” (trans. indigo dyeing) performed at Litmus, known as froth fermentation, uses a dye called “sukumo” derived from true indigo which goes through lye fermentation with only natural materials. Different from synthetic dye that allows high volume coloring, our process is performed with our hands and careful reciprocity with the dye liquid. Since the process depends on the natural changes, each “Ai” born has a different hue of blue and expression even if the submerging of material is repeated. There is never the same result. Each piece has its own expression. We overlay our personal filters onto this technique to offer Japan’s color of “Ai” through nonconventional pieces of work.

The history of indigo dye is deep and colorful. There are sayings of how mummies were wrapped with indigo cloth in ancient Egyptian era. Indigo was told to exist in Japan as far back as the 5th century. Numerous indigo products were discovered in the treasure vaults of Horyuji and Sosoin temples. There is documentation of many samurai who wore clothes woven from indigo threads during the War Age. The color of indigo was known as the color of “Kachi” (brown, indigo’s liquid color). “Kachi” is also the word for “Win” in Japanese and thus, samurai must have entrusted superstitious belief in the color.

In the ancient period, the color of blue could only be achieved with indigo. Since it was very valuable and rare, only persons of the privileged classes could don it. Over time, indigo clothes were more commonly used from the Edo period. Cotton and indigo dye matched well together and indigo dyed material became a part of Japanese life as people believed it turned more durable through repeated dyeing. There was a saying such as “Insects hate clothes dyed with indigo.” People dyed many items such as farming clothes, hand towels, undershirts, floor cushion, and shop curtain. Famous “Ukiyoe” (trans. floating world paintings) artists like Hokusai and Hiroshige used indigo pigment and expressed that era eloquently. The blue referred to as “Hiroshige Blue” attracted worldwide praise.

The indigo dye was widely popular and deeply rooted into people’s lives, but lost popularity rapidly after the influx of chemical dye around the late Meiji period. It is hard to imagine that people grew cotton and indigo by themselves in their farmlands only 100 years ago, but Japan was undoubtedly a country rich in the blue of “Ai.”

Japanese Traditional Lye Fermentation Indigo

The process to make natural indigo dye liquid is called “lye (Aku) fermentation.” Lye fermented indigo means the use of the microbe in the lye that ferments naturally to produce the indigo dye in a vat. This is the Japanese traditional way to make the dye liquid. To prepare the indigo, “Sukumo” (made by composting dried polygonum leaves which takes about 4 months to compost) and coal and boiling water are added to the lye. Then Japanese sake and wheat bran are further added into the vat to stimulate the fermentation. Its temperature must be carefully maintained and it has to be frequently stirred over 2 to 3 days. The foam on the vat’s surface is called “Ai no hana”(indigo flower) and is the sign of healthy fermentation. Furthermore, lye liquid is carefully added over 4 to 5 days to increase the amount of dye. After about 2 weeks of observing its state from dawn till dusk, the fermentation stabilizes and the liquid is finally ready for dyeing.

“Ai” Blue
The color of the prepared indigo dye is dark brown and it has a distinctive smell. The cloth to be dyed is submerged into the vat to absorb the liquid. It is squeezed tightly and spread out to breathe in air. When the cloth is dipped into water, the beautiful Ai blue color appears. Indigo dye is not added directly onto the material. It is the repeated process of oxidization and deoxidization that produces Ai blue. It is also different from the dyeing process with other plants. Fermented indigo is alive and breathing, thus it changes day to day. If you dye too much at one time, the indigo goes bad and doesn’t produce the beautiful color. The liquid needs to be stirred once a day even when you are not dyeing to add air and maintain its stable condition.

Months pass by from the green indigo leaves to the making of the “Sukumo” and to the preparation of the lye. The color of “Ai,” indigo blue is born only through the care of our hands and the passage of time. “Ai” enriches and changes its expression depending on who wears it and how it is worn. We hope that you’ll enjoy the blue of “Ai” that lives and grows with you.