link to the top page | Dyeing Purple from Fresh Leaves of Polygonum tinctorium |
Indigo dyeing can also be performed by soaking cloth or yarn into a juice of fresh leaves of Polygonum tinctorium. Green leaves of indigo plants contain colorless precursor of indigotin
called indican which turns to blue indigotin within the fiber. In the process
of the forming of indigotin, red colorant called indirubin is sometimes
produced. One can obtain purple shade by producing much indirubin. Methods
to get purple from Polygonum is described in this page.
This results are already published and presented in the meeting of DHA
in Edinburgh on Oct.2000.
#Ushida; S. "Method to dye purple from fresh leaves of Polygonum tinctorium", Senshoku alpha(Journal for amateur dyers written in Japanese) No225, pp64-67 (1999)
#Ushida; S., Tanigami; Y. "Dyeing of Silk Fabrics in Red-Purple Shade
with Fresh Leaves of the Japanese Indigo Plant", Nihon Kasei Gakkaishi
(Journal of Home Economics of Japan, i.e. the journal of domestic science
in Japan), Vol.49, No9, pp1033-1036(1998).
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| Silk fabric (4g,for this case) is soaked in 5% sodium carbonate for a while and is dried without wringing. | 20g to 30g of fresh leaves of Polygonum is collected. | ||
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| Cut leaves are stuffed into a sack of gauze. | The sack is tied with a rubber band. | ||
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| The sack is compressed in 500ml of 20%-ethanol solution for about 10 min. | Indican is extracted from the leaves. The solution is allowed to stand for 30min. | ||
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| Silk which was pretreated with alkali is soaked for 30 to 60min. | The silk is submitted to the air oxidation. |
| No.(*) | Ethanol Content of the juice of fresh leaves | Alkali of Pretreatment of Silk Fabrics | Temperature of Dyeing | Shade |
| (1) | 20% | 5% Sodium carbonate | 50 | reddish purple | | | | | bluich purple |
| (2) | 30% | 10% Sodium carbonate | 27 | |
| (3) | 30% | 5% Sodium carbonate | 27 | |
| (4) | 20%(**) | 5% Sodium carbonate | 27 | |
| (5) | 20% | 5% Sodium carbonate | 27 | |
| (6) | 20% | 1.25% Sodium carbonate | 27 | |
| (7) | 20% | 5% Sodium carbonate + 4% Sodium bicarbonate = 3:1 (pH=10.5) | 27 | |
| (8) | 20% | 5% Sodium carbonate + 4% Sodium bicarbonate =1:1 (pH=10.0) | 27 | |
| (9) | 10% | 5% Sodium carbonate | 27 | |
| (10) | 5% | 5% Sodium carbonate | 27 | |
| (11) | 20% | 0.05% Sodium carbonate | 27 | pale green |
| (12) | 40% | 5% Sodium carbonate | 27 | pale green |
| (13) | 20% | 0.08% Sodium carbonate | 27 | light gray |
| * No. in the table correspond to those indicated within the photo below. **Ethanol was added after preparing the juice. |
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No 14 ; Dyed without pretreatment with alkali, i.e. normal method of indigo dyeing with fresh leaves of Polygonum tinctorium.