• Textile Coloration and Finishing
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• v.7 no.4
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• pp.16-24
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• 1995

Traditionally dyeing fabric with dyestuff extracted from Indigo was a popular method of obtaining blue color in the world before synthetic dyestuff was developed in the 1890's. As the Korean traditional process of dyeing extracted from Indigo, there are two kinds of dyeing process; The deposite dyeing of muddy Indigo and the leaf dyeing of Indigo plant. In order to study the properties of leaf dyeing of Indigo, the dyeing properties, color difference on cotton and silk fabrics under several dyeing conditions were investigated. In the dyeing of cotton and silk fabrics with leaf dyeing of Indigo, the dyeing affinity of silk was higher than that of cotton, the cotton and silk fabrics were dyed dark yellowish Green and dark Blue, respectively. the dye uptake increased with the increase of dyeing temperature and of the unmber of dyeing times. When cotton and silk fabrics dyed with leaf dyeing of Indigo at 6$0^{\circ}C$ for six number of times, the K/S value of dyed cotton and silk were calculated 1.286, 2.613 respectively.

• Textile Coloration and Finishing
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• v.24 no.4
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• pp.253-259
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• 2012

In this work, the natural indigo production process from Polygonum tinctorium was balanced based on the traditional Niram method in Korea. A standard procedure was determined considering the conditions of indican extraction from plant material, the amount of alkali for precipitation, storage of extract, etc. The effect of experimental conditions on the yield of crude dye was investigated. The contents of indigo and indirubin of the crude dyes were analyzed by HPLC. Increase of the amount of crude dye was observed within 1-2.5 days of extraction time. Longer extraction beyond 2.5 days resulted in a slight decrease in the amount of crude dye. There was no consistency in terms of indigo content depending on extraction pH. We found that the storage of extract or harvested plants affected adversely to dye yield and dye quality. Based on the lab scale extraction, large scale extraction was performed for 2-2.5 days in water and 2.0-2.5 g/L of $Ca(OH)_2$ was applied for precipitation of indigo dye. We obtained natural indigo dye containing about 15% of pure indigo in scale-up production using whole plant except root.

• Textile Coloration and Finishing
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• v.20 no.3
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• pp.18-24
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• 2008

The purpose of this study is to develop the dyeing method with dry leaves of indigo plant. Coloring matter was extracted from dry leaves of indigo plant with hot sodium hydroxide solution. The extract was reduced with sodium dithionite, and it was used for dyeing cotton fabrics under various conditions. UV-visible absorption spectra of extract, reduction rate of extracts by reducing agent, and the surface color of dyed cotton, lightfastness were examined. For the initial 20 minutes, the absorbance of indigo solution rapidly decreased. However, several hours later, the decreasing rate retarded. By repeating the dyeing process, the shade looked deeper and deeper. At $30-40^{\circ}C$, the value of K/S reached the highest point. The concentration of indigo solution in dye bath seemed to playa critical role for the reaction of the reducing agent. It was observed that the surface color of cotton fabrics was getting bluish and its degree of value and chroma seemed slightly decreased as the K/S value was increasing. The lightfastness was clearly enhanced by increasing the K/S value.

• Journal of the Korean Society of Clothing and Textiles
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• v.34 no.12
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• pp.1933-1946
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• 2010

This paper is a comparative analysis of the $19^{th}$ century practice of indigo dyes and dyeing in Korea and England. From over hundreds species of indigo plants in the world, it was dyer's knotweed and woad that were cultivated in Korea; however, the only indigo plant grown in England was woad. Indigo dye was produced in the form of damp indigo sediment (jeon) in Korea; however, imported indigo (as a main dye) and couched woad (as an additional dye) were indigo dyes used in England. There existed three kinds of indigo vats, the ice vat, ash-water vat, and indigo sediment (jeon) vat, in Korea. The fresh leaves of indigo were used for both the ice vat and ash-water vat. The ice vat was very convenient for preparation, but had a weakness in the inability to produce a very deep shade of blue. The ash-water vat and indigo sediment (jeon) vat were in use for producing a very deep shade of blue. The indigo sediment Goon) vat was employed presumably only by professional dyers. The indigo vat practiced in England was categorized into two types; one was woad-indigo vat, and the other was an indigo powder vat prepared by using imported indigo rock. There was a tendency to adopt different kinds of indigo vats according to the material to be dyed. The woad-indigo vat was employed for the dyeing of wool. A few of chemical vats with imported indigo were adopted, especially for the dyeing of cotton. Indigo dyers in 19th century Korea were differentiated from the rest of the dyers. They managed the growing of indigo plants as well as the production of indigo sediment (jeon). Woad dyers in 19th century England handled woolen cloth as well as worsted and woolen yarn in general. However, they sometimes dyed silk skein as well. They produced several colors such as black, blue, slates, grays, by using both woad and imported indigo.

• Textile Coloration and Finishing
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• v.16 no.5
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• pp.19-27
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• 2004

The dyeing on cellulose fibers such as cotton and viscose viscose rayon was carried out by the use of solution extracted from natural fresh leaves of indigo plant under several dyeing conditions. The dyeing affinity of viscose rayon was higher than that of cotton. The total K/S value of dyed fabrics was considerably increased with repeated dyeings, while a dyeing time has a little influence on it. Both fibers were hardly dyed by indigo at $60^{\circ)$ and cotton was dyed better at $40^{\circ)$ than at $20^{\circ)$, but in viscose rayon, a little difference of total K/S was shown between $20^{\circ)$ and $40^{\circ)$. The color change of dyed fabric according to dyeing conditions was evaluated by the CIELAB color system. viscose rayon had a lower $b^*$ so that it looked bluer than cotton and when the celluose fibers were dyed by indigo plant at the lower temperature, the bluer it looked. By repeated dyeings the $b^*$value of dyed fabrics was much increased but the $a^*$ value was little influenced and in case of viscose rayon the change was considerable.

• KSBB Journal
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• v.28 no.5
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• pp.295-302
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• 2013

Indigo is utilized in various industries including textile dyeing, cosmetics, printing and medicinal products and its reduced form, leuco-indigo, is mainly used in these process. Chemical reducing agent (sodium dithionite, sodium sulfide, etc.) is preferred to use for the formation of leucoindigo in industry. In traditional indigo fermentation process, microorganisms can participate in the reduction of indigo and thus it has been known to reduce environmental pollution and noxious byproducts. However, in fermentation method using microorganisms it is difficult to standardize large scale production process due to low yield and reproducibility. In this study, we attempted to develop the indigo reduction process using microbial flora which was isolated from naturally fermented indigo vat or deduced by metagenomic approach. From the results of library analyses of PCR-amplified 16S rRNA genes from the traditional indigo fermentation vat sample (metagenome), it was confirmed that Alkalibacteriums (71%) was distinctly dominant in population. Some strains were identified after confirming that they become pure culture in nutrient media modified slightly. Four strains were separated in this process and each strain showed obvious reducing ability toward indigo in dyeing test. It is expected that the analyzed results will provide important data for standardizing the natural fermentation of indigo and investigating the mechanism of indigo reduction.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.57 no.3
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• pp.209-214
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• 2012

Indigo crop, Persicaria tinctoria H. Gross is an annual plant containing natural colorant, the blue dye indigo, and local cultivars had been cultivated to produce natural indigo for textile dyeing in Korea since ancient times. Naju No. 2 is a new mass-selected line from the mother population, Naju Local cultivar. In this study, two breeding lines of Naju Local and Naju No. 2, have been cultivated in four different locations, the South regions of Korea, to compare plant growth and yield characteristics between two lines. Naju No. 2 was higher in plant height, and Naju Local has more 1st branches. Naju No. 2 has larger leaf area and higher width/length ratio of leaf, showing the round leaf type as morphological stable character without regional differences. Though there was considerable regional variation in fresh and dry top weight of harvested plant, the significant difference of plant weight between two lines were not shown. The ratio of leaf to total shoot of dry weight of Naju No. 2 was higher than one of Naju Local, indicating that Naju No. 2 has better yielding of colorant which is synthesized mostly in leaf. Naju No. 2 contained more Niram (crude indigo extract) and indigo, and showed much blueness at dyeing of silk using fresh leaves than Naju Local. We concluded that a new line, Naju No. 2 could be a superior cultivar due to having higher leaf yield and better quality of natural colorant than Naju local cultivar.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.51 no.spc1
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• pp.247-250
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• 2006

We herein studied the effect of polyamines (putrescine, spermidine and spermine) on growth and indigo biosynthesis in hairy root cultures of Polygonum tinctorium Lour. Our results revealed that polyamine treatment increased hairy root growth and indigo biosynthesisat all tested concentrations, with the highest growth rate (4.4 g/ flask) and indigo yield (216 ug/g) induced by 70 mg/L putrescine. These results show far the first time that the growth rates and indigo biosynthesis of Polygonum tinctorium hairy roots may be improved by addition of polyamines to the liquid culture medium.

• Journal of the Korean Home Economics Association
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• v.45 no.4
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• pp.53-59
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• 2007

We need to diversify the colors by natural dyeing for promotion and extention of the natural dyes market, because natural dyestuffs have the limitation the number of the colors to express, compare to synthetic dyestuffs. It was investigated that wool and silk fabrics could be dyed to green colors using natural mugwort and indigo as one of color diversification, in order to express green color that is difficult to be shown by natural dyeing. The mugwort dyebath was prepared to concentration of $25{\sim}100g/l$ using dried mugwort plant and indigo dyebath was prepared to concentration of $5{\sim}20g/l$ using natural indigo powder. Wool fabrics and silk fabrics were dyed to green(GY, G, BG in Munsell color wheel) by two batch methods using the mugwort and indigo dyebaths. the mugwort dyeing was applied at $80^{\circ}C$ for 20minutes and indigo dyeing applied for $5{\sim}7$ minutes in room temperature. The colorfastness to drycleaning and abrasion of the dyed fabrics were shown good as grade 4-5 or 5.

• Journal of the Korean Society of Clothing and Textiles
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• v.18 no.2
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• pp.221-233
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• 1994

In several literature in China were recorded various species of the indigo genus, but in Chosen documents, the two have been intensively mentioned, that is, Polygonum tinctorium (PT) and liatis Tinctuna(IT). Allowing for some slight contradictions of the records between the two countries, we insist that J)T is the aborigines historically longer than any other indigo plant in Korea and that IT is the one Implanted from China in late Chosen period. Indigos can be grouped into two major categories : 'Chon' or Indigo forming sediment in the course of making, and 'Nam' or the one without. The dyestuffs of blue, or dark blue tineged with red, which had been ocasionally recorded until the mid Chosen, could be made from the . species without sediment. The period when the color thus obtained was prevalent can be traced back to the era of Yongio, when the import of blue-dyed textiles from China was prohibited to encourage the domestic dyeing industry. However, a more clarification is needed on this matter, since all of the previous researches are arguing, with little validity, that the indigo genus in Korea be PT. Judging from the documents recording that PT did not form any sediment, and that from it was obtained only light color like indigo, it is a matter of re-discussion in terms of botanical taxonomy to define as PT the species being cultivated in some areas in Chollanam-do. In conclusion, a joint research, including specialists in traditional dyestuffs and in botany in relation to the taxonomical problem of the indigo genus, would be expected for further Investigation on this matter.