The Dyer's Art
Most of the natural blues, reds, blacks, purples, and browns on traditional Indonesian textiles derive from two vegetable dyes: indigo blue, from the shrubs Indigofera tinctoria and Indigofera suffruticosa, and morinda red, from trees in the genus Morinda. With patience and skill, master dyers carefully manipulate each ingredient in a dye recipe and each step in the dyeing process to obtain bright, muted, energetic, or quiet colours.
Dyers pound the root bark of Morinda trees and wring it in water to extract a red pigment called morindin. Morindin does not adhere to cotton without a mordant, a combination of organic compounds that binds the colour to the thread. A mordant requires oil, tannin, and an aluminium salt, chemicals that occur naturally in particular forest plants. Secret mordant recipes have been passed down from mother to daughter for generations.
Most traditional mordant recipes start with an oily paste made from pounded candlenuts (Aleurites moluccana) mixed with an alkaline water filtered through wood ash, essentially making a soap. Many wild plants contain tannin; each dyer adds her local favourite to the mixture. The aluminium salt comes from the powdered leaves and bark of trees in the Symplocos and Xanthophyllum families. In eastern Indonesia these trees grow mostly at high altitudes and lowland dyers get the leaves they need through trade.
The more slowly the mordanted yarns dry, the stronger the final red will be. The East Sumbanese slow the process by leaving mordanted threads out overnight to take the dew, and shading them by day. In Kalimantan, Dayak weavers gather together, mordant threads, and ask the blessing of the gods and ancestors with a ritual called ngaos.
Dyers repeat the morinda process over and over to achieve depths and variations of red. The East Sumbanese like vibrant reds that ring with vitality. The Lio-Ende people of Flores dye their threads in morinda up to ten times, then dip them in a hot solution made from sappan-wood (Caesalpinia sappan), which deepens the red to a distinctive earthy brown. Mordanting and dyeing can take a diligent dyer two years.
The nitrogen-fixing indigofera shrub thrives in poor soils. An indigo dyer collects great armfuls of indigo leaves and soaks them in water overnight to release the precursor of the blue dye. When the dyer removes the leaves and adds slaked lime made from burnt limestone or seashells doused with water, the alkaline solution turns yellow-green. At this stage, the dyer can immerse threads in the vat. Upon exposure to air, the dye oxidises and turns blue, dyeing the threads.
Most weaving and dyeing takes place during the dry season, long after indigo plants have died. To store indigo, the dye-maker aerates the yellow-green solution thoroughly, until a blue sludge of oxidised dye settles at the bottom of the vat. This concentrate can be stored as paste, or dried into cakes. Months later, the dyer can make a new dye vat by mixing the paste or powder with water to increase its volume, with slaked lime to increase the alkalinity, and with certain roots and bark as sources of sugar that act as a reducing agent. With reduction and oxidation being opposite chemical processes, the indigo is first reduced to make it soluble, then penetrates the yarn upon dyeing, and then is oxidised in the air to make it insoluble and bound to the fibre being dyed.
The weavers of Tenganan, Bali, make their own red dye, but a cultural taboo requires that no indigo work be done within the village. For centuries, Tenganan has sent half-finished dye lots to the neighbouring community of Bugbug, where one family has come to specialise in indigo dyeing. The Sumbanese believe that if at any time a man enters the indigo dyeing hut, the colour will not take.
Repeated indigo dyeing produces a very dark blue that never reaches a true black. To make black, some weavers add tannin plants to their indigo vats, or over-dye indigo with tannin and iron. The black mud in Rindi, East Sumba, is particularly rich in iron and other minerals. Weavers in Rindi soak tannin-dyed threads in mud-holes to obtain an even, colourfast black.
Yellows and Greens
Colourfast greens and yellows are very difficult to produce. Turmeric root (Curcuma domestica) contains a vivid yellow that fades quickly in open air and sunlight. Pounded leaves make beautiful chlorophyll greens, which also degrade quickly. More durable yellows can be extracted from combinations of mango bark (Mangifera indica), jackfruit wood (Artocarpus integra), and Maclura cochinchinensis heartwood. These dyes can be combined with indigo for a stable, colourfast green.
Saving Dye Practices
Every year, Threads of Life’s partner organisation the Bebali Foundation (ypbb.org) conducts hundreds of experiments at its Bali dye studio. The Bebali Foundation’s researchers test plant varieties from throughout the archipelago in countless combinations as they explore and document weavers’ knowledge. With help from the studio, communities are rediscovering their ancestors’ dye processes, sharing techniques across ethnic and geographical boundaries, and learning to manage their dye resources sustainably.