Touched by Indigo - Royal Ontario Museum
Touched by Indigo - Royal Ontario Museum
Touched by Indigo - Royal Ontario Museum
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INDIGO<br />
The Chinese obtain blue dye from<br />
several plants. Among them the liaolan<br />
(Polygonum tinctorium) is the most<br />
popular. This is an annual herbaceous<br />
plant having alternating bluish-green<br />
leaves on a fleshy stem. Its small flowers<br />
range in shade from white to dark<br />
pink. Some believe that the pink-flower<br />
varieties yield more dye than the white<br />
ones.<br />
Liaolan has been cultivated in<br />
China since the Zhou dynasty. Over<br />
time, this useful plant became more and more widely grown. In<br />
China's eastern province of Zhejiang, the best indigo is produced<br />
from the village of Huangtandong near the city of Yueqing. Their<br />
traditional method of production is briefly described here.1<br />
The plant is harvested in mid-October when it reaches about 85<br />
cm tall. Women and children help to pick the leaves and tender twigs<br />
that will be used to make indigo dye. The denuded stalks are then cut<br />
at about 4 cm above the ground, tied into bundles, and stored away<br />
to be replanted in the spring.<br />
The production process, which takes approximately twenty<br />
days, is undertaken <strong>by</strong> men only. It takes place on a gentle slope<br />
in the field where three artificial ponds have been dug.<br />
The largest, measuring 2 m in diameter and 1 m deep,<br />
is situated in the middle. It is flanked <strong>by</strong> two smaller<br />
ones located one above and the other below. During the<br />
first week, the leaves and twigs are thoroughly soaked<br />
in water in the big pond. They need to be stirred three<br />
times a day to ensure even fermentation and release of<br />
the dye matter.<br />
The decomposed leaves and twigs are then scooped<br />
up and placed in the upper pond. At this time slaked lime<br />
(calcium hydroxide) is added to the liquid left in the big pond.2 This<br />
step needs great care since the amount added is critical to the quality<br />
of the end-product. First, two people<br />
use a wooden bucket with two long<br />
upright handles to scoop out some liquid.<br />
While one person keeps stirring the<br />
liquid in the bucket, the other adds the<br />
slaked lime. When a suitable amount<br />
has been added, they lower the bucket<br />
into the pond until its rim is about the<br />
same level as the liquid in the pond.<br />
Turning the bucket in a circular motion<br />
all the time, they gradually add the<br />
mixed liquid to the indigo in the pond,<br />
taking care not to let the residues in the<br />
bucket spill over into the pond. This<br />
step has to be repeated four times. How<br />
much slaked lime should be mixed into<br />
the indigo is judged <strong>by</strong> tasting. When<br />
the indigo is bitter to the taste, it means it has attained its optimum<br />
alkalinity.<br />
The next step must be done either before sunrise or after sunset<br />
so the dye-maker can judge the hue of the indigo unaffected <strong>by</strong> sunlight.<br />
Standing on opposite sides of the pond,<br />
each man uses a wooden plough to push and<br />
stir the liquid towards the centre. Thirty minutes<br />
of this vigorous stirring causes a thick<br />
and fast-moving frothy foam to gather on<br />
the surface. When the foamy layer reaches a<br />
height of 30 cm, one of the men adds a few<br />
spoonfuls of vegetable oil. At this point they<br />
switch tools, now using skimpily constructed<br />
long-handle scoops to continue to stir and