• Science of Emotion and Sensibility
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• v.21 no.1
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• pp.143-154
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• 2018

This study was performed in order to suggest useful data for color planning of eco-friendly and sensible fashion products. Silk fabrics were dyed in combination with natural indigo and Japanese pagoda tree and were treated with four kinds of mordants after combination dyeing. Then, their colorimetric properties were evaluated. From these composite-dyed silk fabrics, color sensibilities and color preferences of green yellow (GY) color were evaluated among the female university students, and thus, the influences of colorimetric properties and color sensibilities on color preferences were analyzed. When the silk fabrics were dyed in the combination of natural indigo and Japanese pagoda tree and were treated without mordants, they turned green color when indigo 10 g/L was used, and blue-green when indigo 20 g/L was added. And when they were dyed in combination of natural indigo and Japanese pagoda tree and were treated with four kind of mordants after combination dyeing, they turned GY color in almost all cases. The color sensibilities of the GY silk fabrics with the combination dyeing of indigo and Japanese pagoda tree, were classified into three factors: pleasantness, gracefulness, and comfort. Color sensibility factors showed significant differences according to the concentration of indigo and the kinds of mordants. There were almost significant relationships between colorimetric properties and color sensibilities factors of compositely dyed GY silk fabrics. The color preferences of the GY fabrics, which were dyed in the combination of using natural indigo and Japanese pagoda tree and four kinds of mordants, were found to be predicted by the color sensibility in a regression model.

• Journal of Sericultural and Entomological Science
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• v.44 no.2
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• pp.93-98
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• 2002

Effect of reducing agent sodium hydrosulfite on the natural indigo on the silk fabrics were examined to improve traditional dyeing method. K/S values of dyed fabrics was monitored with various dyeing temperature time, amount of dye and reducing agent. The dyeability of silk fabrics was improved by using reducing agent, sodium hydrosulfite; K/S value (7.20) was higher then that (1.09) of traditional method at the frist dyeing. Natural indigo dye extracted from dyed silk fabrics are composed of isomer, indigo (67.3%) and indirubin (32.5%). However, silk fabrics showed excellent anti-microbial activity regardless of the dyeing methods.

• The Research Journal of the Costume Culture
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• v.28 no.5
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• pp.669-676
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• 2020

The purpose of this research was to revive the bathochromic effects of wool fabrics by using natural dyestuffs with minimum heavy metallic mordants. The natural dyestuffs used in this research were the indigo plant, Phellodendron amurense, and Caesalpinia sappan. Sample no. 1 was pre-dyed five times with indigo. Sample no. 2 was pre-dyed five times with indigo and then once dyed with Phellodendron amurense. Following the same method as sample no. 2 with an additional Phellodendron, Sample no. 3 consisted of a pre-dye five times with indigo and twice with Phellodendron amurense. Sample no. 4 was pre-dyed six times with indigo and then once dyed with Caesalpinia sappan. Sample no. 5 followed the same method as no. 4 with an additional dye of Caesalpinia sappan. Sample no. 6 was pre-dyed five times with indigo and then once dyed with Phellodendron amurense and once dyed with Caesalpinia sappan. The results were as follows: first, all samples showed deeper colors. Second, according to the results of the surface K/S measurement, the surface K/S of wool fabrics was >20. Third, the results of lightfastness measurement showed superiority over grade 4 in samples no. 1, 2, 3, 5, and 6. However, sample no. 4 was grade 3. In the colorfastness to washing measurement, sample no. 2 showed greater superiority than grade 3-4, while samples no. 1 and 3 were grade 3. In addition, the colorfastness to dry cleaning for all samples was satisfactory or excellent by more than grade 3.

• Science of Emotion and Sensibility
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• v.20 no.3
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• pp.3-12
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• 2017

This research was carried out in order to suggest useful data for planning fabrics of summer eco-friendly fashion products. For this purpose, four cellulose fabrics were dyed with natural indigo under three different dyeing conditions, then, their colorimetric properties and color sensibilities were evaluated, and their influences on color preferences were analyzed. All cellulose fabrics naturally dyed with indigo showed the characteristics of PB color tones, middle and low value, and low chroma. Color characteristics were significantly different according to fiber type and dyeing condition. The color sensibilities of the fabrics dyed with indigo were classified into three factors: sporty, classic and natural. These sensibilities showed partially significant differences according to fiber type and dyeing condition. Also, there were partially significant relationships between color characteristics and the color sensibilities of the fabrics dyed with indigo. The color preferences of the dyed fabrics with indigo were found to be influenced by the sporty and classic of color sensibility and $L^*$ of color characteristics.

• 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.

• Journal of the Korean Society of Clothing and Textiles
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• v.34 no.3
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• pp.508-517
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• 2010

One-step reduction/dyeing method was optimized for wool dyeing with natural indigo dye in this study. The effects of reduction/dyeing conditions including dye temperature and time, the pH of bath, concentration of dye, and reducing agent on dye uptake and color were investigated. The dye uptake was higher with no addition of alkali. Dyeing was carried out through the use of only sodium hydrosulfite in the bath. The maximum dye uptake was obtained at $60^{\circ}C$ for 30min and the dyed fabrics appeared in the PB Munsell color range. Dye uptake improved with the increase of a natural indigo dye concentration with the same sodium hydrosulfite concentration. At a higher dye uptake, the fabric color became more purplish and the maximum absorption shifted from 660nm to 620nm. Color reproducibility was reliable with a color difference in the range of 0.41~1.43. Regardless of color strength, washing and dry cleaning fastnesses were good with a 4/5 rating, and fastnesses to rubbing and light were acceptable with a 3/4~4 rating.

• Textile Coloration and Finishing
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• v.29 no.4
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• pp.276-283
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• 2017

The aim of this study is to develop an effective dyeing process for black color on the silk fabrics, using natural Indigo, Madder, Amur cork tree, Alder, Logwood, and Gallnut. All natural dye materials were water-extracted, concentrated, and freeze-dried. Seven different processes were carried out and the color differences(${\Delta}E$) of black color with each process from the chemical black dyed fabric were compared. The light, washing, and rubbing fastness were evaluated. The black dyeing of the silk fabrics was well carried and excellent black color was obtained in every methods. The profound black color could be obtained by the subtractive mixture of the three primary colors of red, yellow, and blue in the order of indigo(blue) - amur cork tree(yellow) - madder or lac(red). Black color was efficiently obtained by iron mordant when logwood or alder fruit was used. The color difference(${\Delta}E$) from the black color with chemical dyestuff was the lowest in the indigo - amur cork tree - lac - iron method. Light fastness and washing fastness were excellent in all dyeing processes, showing grade 5. The fastness to rubbing was excellent as shown grade 5 in the dry samples of logwood - iron process and alder fruit - iron process.

• Journal of the Korean Society of Clothing and Textiles
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• v.32 no.12
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• pp.1963-1970
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• 2008

Natural indigo dye in powder form was prepared by modifying traditional Niram method, using $Ca(OH)_2$ instead of baked oyster powder for precipitating indigo dye. The prepared dye was applied to dyeing Tencel fabrics to investigate the effect of experimental conditions for the optimization of dyeing process. The indigo dye powder contained 15.2%(w/w) of indigo content and 0.757%(w/w) of indirubin content on the basis of HPLC analysis. Maximum dye uptake was obtained at $60^{\circ}C$ for 20min. Almost saturated dye uptake was obtained at 2g/L of sodium hydrosulfite concentration up to 4g/L of indigo dye and then slowly increased for further increase of sodium hydrosulfite. Whereas at higher indigo dye concentration(8g/L) more than 3g/L of reducing agent concentration was required for obtaining the maximum dye uptake. At the same indigo dye and reducing agent concentration, K/S value of the sample dyed without sodium hydroxide(pH 5.75) was 15.19, much higher than one dyed in alkaline condition(K/S 5.76). There was no difference in colorfastness ratings among samples with different color strength. However, more fading was occurred for the sample with low color strength.

• Fashion & Textile Research Journal
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• v.13 no.2
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• pp.263-268
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• 2011

One-step reduction/dyeing method was applied for ramie dyeing with natural indigo powder. The effect of reduction/dyeing conditions including the pH of bath, dye temperature and time, and concentration of indigo powder and reduction agent on dye uptake and color properties were investigated. Regardless of addition of alkali, the dyed fabrics appeared in the PB Munsell color range(${\lambda}_{max}$: 660 nm) and the dye uptake was much higher with no addition of sodium hydroxide. Dyeing was carried out through the use of only sodium hydrosulfite in the bath. The maximum dye uptake was obtained at 60 for 30min. Saturated dye uptake was obtained at 2 g/L of sodium hydrosulfite concentration up to 2 g/ L of indigo powder. Whereas, at higher indigo powder concentration (4 g/L), more than 3 g/L of reducing agent concentration was required for obtaining the saturated dye uptake. Color reproducibility was reliable with color difference in the range of 0.03~0.16. Regardless of color strength, fastness to rubbing was acceptable with a 3/4~4/5. Fastness to washing, dry cleaning, and light of samples with low color strength were poor. Whereas, fastness to washing, dry cleaning, and light of samples with high color strength were very good.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.48 no.3
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• pp.57-65
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• 2016

Indigo (Polygonum tinctorium L.) is a typical blue dye which had been used from ancient times. This study was going to shade the complicated traditional methods extracting indigo dye by the fermentation and producing as adsorbate on calcium hydroxide, which says so called as the 'Indigo lime'. Accordingly we were going to make indigo through the hydrolysis of the hot water extractives of indigo leaves simply. During hot-water extraction, ${\beta}$-glucosidase which required hydrolysis of the linkage between indigo and glucose was not activated. To achieve this goal, indican was acid-hydrolyzed to glucose and indigo. The acetic acid, citric acid, hydrochloric acid, and sulfuric acid were used for the hydrolysis of hot water extractives. The hydrolysis conditions of extractives performed in water bath at $80^{\circ}C$ for 120 minutes and in an autoclave for 120 minutes. In the acid hydrolysis of extracted indican by hot water, the indican yields of acetic acid and hydrochloric acid hydrolysis were higher than sulfuric acid in water bath. Also, the indican yield of hydrochloric acid hydrolysis was better than sulfuric acid in autoclave. The hot water extracted indican was confirmed by HPLC analysis and its structure was confirmed by UV-Vis and FT-IR spectroscopy, compared with isolated indigo and commercial synthesized indigo. This improved extraction and hydrolysis methods can be replace the traditional indigo making method.