PROSEA, Introduction to Dyes and tannins - Revision history

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	Table 1. Alphabetical list of important dye producing plants with another primary use. Scientific name, family name, vernacular name, part of the plant used for dyeing, colouring substance and colour, and material suited for dyeing are given, where known. See Chapter 4 for commodity group and synonyms.		Table 1. Alphabetical list of important dye producing plants with another primary use. Scientific name, family name, vernacular name, part of the plant used for dyeing, colouring substance and colour, and material suited for dyeing are given, where known. See Chapter 4 for commodity group and synonyms.

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	Table 2. Alphabetical list of important tannin producing plants with another primary use. Scientific name, family name, vernacular name, part of the plant used for tanning, percentage tannin on dry weight basis, and material suited for tanning are given, where known. See Chapter 4 for commodity group and synonyms.		Table 2. Alphabetical list of important tannin producing plants with another primary use. Scientific name, family name, vernacular name, part of the plant used for tanning, percentage tannin on dry weight basis, and material suited for tanning are given, where known. See Chapter 4 for commodity group and synonyms.

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	*''Symingtonia populnea'' (Hamamelidaceae): bark, containing ca. 11% tannin, used for tanning leather.		*''Symingtonia populnea'' (Hamamelidaceae): bark, containing ca. 11% tannin, used for tanning leather.
	*''Syzygium'' spp. (Myrtaceae): bark, containing up to 28% tannin, used for tanning fishing nets.		*''Syzygium'' spp. (Myrtaceae): bark, containing up to 28% tannin, used for tanning fishing nets.

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History and role of vegetable tannins

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	In 1851 chrome tanning was discovered, and this rapidly took a major place in the commercial world. In chrome tannage the animal skin is impregnated with chromium salts. Later, with the development of the chemical industry and the knowledge of organic synthesis, it became possible to build molecules into synthetic tannins, which have a more specific activity and are more predictable and controllable in the tanning process. The use of synthetic tanning materials such as syntans, resin tannages and aldehyde tannages, has increased rapidly since 1950. The synthetic tannins allow the tanner to obtain special effects in processing or leather quality (Thorstensen, 1985). In the United States about 85% of all leather is tanned by mineral processes and about 15% by vegetable tanning processes (Seigler et al., 1986).		In 1851 chrome tanning was discovered, and this rapidly took a major place in the commercial world. In chrome tannage the animal skin is impregnated with chromium salts. Later, with the development of the chemical industry and the knowledge of organic synthesis, it became possible to build molecules into synthetic tannins, which have a more specific activity and are more predictable and controllable in the tanning process. The use of synthetic tanning materials such as syntans, resin tannages and aldehyde tannages, has increased rapidly since 1950. The synthetic tannins allow the tanner to obtain special effects in processing or leather quality (Thorstensen, 1985). In the United States about 85% of all leather is tanned by mineral processes and about 15% by vegetable tanning processes (Seigler et al., 1986).
	In large tanneries vegetable tannins are especially used for "heavy leathers"" such as soles, belts, straps and mechanical leathers. The processes involved are time consuming. It can take 2 months or more to tan sole leather (Thorstensen, 1985). The vegetable tannin imparts the property of mouldability to sole leather and gives more physical weight and better durability. The major vegetable tannins are available as powders. In large tanneries, they are usually mixed with syntans.		In large tanneries vegetable tannins are especially used for "heavy leathers" such as soles, belts, straps and mechanical leathers. The processes involved are time consuming. It can take 2 months or more to tan sole leather (Thorstensen, 1985). The vegetable tannin imparts the property of mouldability to sole leather and gives more physical weight and better durability. The major vegetable tannins are available as powders. In large tanneries, they are usually mixed with syntans.

	Chrome tanning is preferred for many types of leather, mainly because chrome tanned leather is more heat proof, stronger and more supple and elastic, is more water repellent, and is easier to dye (van Herwijnen, 1956). Chrome tannins are therefore used for shoe upper leather and light leathers. The chrome tanning for upper leather is a rapid process taking only a few days. However, vegetable re tannage of chrome tanned leather is often necessary to produce usable leathers, and numerous light leathers are subjected to vegetable tanning to develop special characteristics.		Chrome tanning is preferred for many types of leather, mainly because chrome tanned leather is more heat proof, stronger and more supple and elastic, is more water repellent, and is easier to dye (van Herwijnen, 1956). Chrome tannins are therefore used for shoe upper leather and light leathers. The chrome tanning for upper leather is a rapid process taking only a few days. However, vegetable re tannage of chrome tanned leather is often necessary to produce usable leathers, and numerous light leathers are subjected to vegetable tanning to develop special characteristics.
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	=== The production of leather ===		=== The production of leather ===

	Leather is remarkable for possessing a combination of properties: it can be hard and tough, but also soft and flexible; it has a porous structure which enables it to "breathe""; it is easy to work and cut. Many attempts have been made in recent decades to produce substitutes for leather, but none of the products equals the particular properties of leather.		Leather is remarkable for possessing a combination of properties: it can be hard and tough, but also soft and flexible; it has a porous structure which enables it to "breathe"; it is easy to work and cut. Many attempts have been made in recent decades to produce substitutes for leather, but none of the products equals the particular properties of leather.

	Leather has for millenia not only been used for clothing; it has also been made (and is still made) into all kinds of tackle and gear such as saddles and reins. It is used to make bags for carrying liquids, and for luggage, purses and wallets, and also as ornament or decoration. Leather covered furniture is currently fashionable in many prosperous countries.		Leather has for millenia not only been used for clothing; it has also been made (and is still made) into all kinds of tackle and gear such as saddles and reins. It is used to make bags for carrying liquids, and for luggage, purses and wallets, and also as ornament or decoration. Leather covered furniture is currently fashionable in many prosperous countries.
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	The tannins must be extracted from the vegetable tissues (often barks). In the past tannins were extracted in open tanks by allowing hot water to percolate through the bark. The resulting tan liquors were diluted. This made it unpractical to transport extracts over great distances, and consequently tanneries were often located near clusters of tannin producing plants. Nowadays the liquors can be concentrated and solidified, and shipping is much easier.		The tannins must be extracted from the vegetable tissues (often barks). In the past tannins were extracted in open tanks by allowing hot water to percolate through the bark. The resulting tan liquors were diluted. This made it unpractical to transport extracts over great distances, and consequently tanneries were often located near clusters of tannin producing plants. Nowadays the liquors can be concentrated and solidified, and shipping is much easier.
	For industrial production of sole leather the hides are first trimmed, soaked, and, if necessary, remnants of flesh are removed. Then they are placed in lime to remove the hair; this usually takes about a week. After treatment with deliming and detergent materials, the hides are ready for tanning. Usually a series of rockers is employed in which the concentration of the tanning materials starts out low and is gradually increased as the tannage proceeds. This takes about 3 weeks. The "butt"" (i.e. the thick part of the hide corresponding to the animal's back and sides after trimming off shoulders and belly) is the most valuable part of the skin for sole leather, and is cut off and halved into "bends"". The bends are tanned again for some weeks and then cleaned and bleached. Finally, the leather is treated with certain oils and chemicals, rolled with a heavy cylinder, and sponged with wax coating materials and dried.		For industrial production of sole leather the hides are first trimmed, soaked, and, if necessary, remnants of flesh are removed. Then they are placed in lime to remove the hair; this usually takes about a week. After treatment with deliming and detergent materials, the hides are ready for tanning. Usually a series of rockers is employed in which the concentration of the tanning materials starts out low and is gradually increased as the tannage proceeds. This takes about 3 weeks. The "butt" (i.e. the thick part of the hide corresponding to the animal's back and sides after trimming off shoulders and belly) is the most valuable part of the skin for sole leather, and is cut off and halved into "bends". The bends are tanned again for some weeks and then cleaned and bleached. Finally, the leather is treated with certain oils and chemicals, rolled with a heavy cylinder, and sponged with wax coating materials and dried.

	The activities connected with the tanning processes can be environmentally destructive. Mangrove forests have been destroyed in several regions for the production of tannins and firewood, and wild populations of quebracho in South America have been locally overexploited. Tanneries produce large amounts of waste solids and chemicals; effluent treatment is now often one of the major considerations in the design and operation of a tannery.		The activities connected with the tanning processes can be environmentally destructive. Mangrove forests have been destroyed in several regions for the production of tannins and firewood, and wild populations of quebracho in South America have been locally overexploited. Tanneries produce large amounts of waste solids and chemicals; effluent treatment is now often one of the major considerations in the design and operation of a tannery.

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History and role of vegetable dyes

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WikiSysop: /* Tannin and animal skin proteins */

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Tannin and animal skin proteins

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	Because of the molecular and macroscopic structure of the proteins, it is clear that stereochemistry is important in relation to tanning. One of the characteristics of leather is its decreased hydrophilic property; another is its stability against rotting. These two may be linked. If the molecules of the tannin are too small (molecular weight M < 500) there is little or no reaction. The reasons for this are not clear. If the molecules of the tannin are too large (M > 3000) they physically prevent a complete reaction along the polyphenol molecule. Not all of the polyphenols with a molecular weight between 500 and 3000 have tanning properties because there must be a stereochemical resemblance between the tannin and the protein.		Because of the molecular and macroscopic structure of the proteins, it is clear that stereochemistry is important in relation to tanning. One of the characteristics of leather is its decreased hydrophilic property; another is its stability against rotting. These two may be linked. If the molecules of the tannin are too small (molecular weight M < 500) there is little or no reaction. The reasons for this are not clear. If the molecules of the tannin are too large (M > 3000) they physically prevent a complete reaction along the polyphenol molecule. Not all of the polyphenols with a molecular weight between 500 and 3000 have tanning properties because there must be a stereochemical resemblance between the tannin and the protein.

	~~1.3.4~~ Tanning practice		=== Tanning practice ===

	In the laboratory, extractions of tannins and other polyphenols are made with methanol. In the leather industry, warm water is used for extraction. The plant extracts consist of tanning and non tanning components. The more the tannin content exceeds the non tanning material in the extracts, the more suitable the plant is as a tannin supplier.		In the laboratory, extractions of tannins and other polyphenols are made with methanol. In the leather industry, warm water is used for extraction. The plant extracts consist of tanning and non tanning components. The more the tannin content exceeds the non tanning material in the extracts, the more suitable the plant is as a tannin supplier.

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	1 Introduction		<center>'''Introduction'''</center>

	1.~~1 Choice~~ of species described in this volume		== Choice of species described in this volume ==

			This volume deals with plants producing substances used as dye or tannin in South East Asia. Dyes and tannins are closely related. Certain plants (e.g. ''Phyllanthus emblica'' L.) contain substances that can be used for dyeing and others that can be used for tanning. As well as being used for tanning, tannins are often also used for dyeing or staining; for example, the dark coloured extract obtained by boiling chips of the heartwood of ''Acacia catechu'' (L.f.) Willd. known as "catechu"" is employed both for dyeing and for tanning. The basic components of many vegetable dyes are chemically comparable with those of tannins. For these reasons vegetable dyes and tannins have been dealt with together in one volume.

			The species (genera) described are primarily used as dye or tannin, and have some economic importance (at least locally). Mangrove species are perhaps primarily used locally for firewood, charcoal and timber, but because they play a major role in the tanning industry, they have also been included. Similarly, ''Phyllanthus emblica'' L. and ''Terminalia catappa'' L. have been included here, even though they are also important for their edible fruits. Some dye and tannin producing plants are poorly known. Their use is occasional and very local, and they have been classified as "dye and tannin producing plants"" because they have no other uses; most of these species are presented in this volume in Chapter 3 "Minor dye and tannin producing plants"".

			In some cases, plants that do not occur naturally or in cultivation in the Prosea region are described because they may have interesting prospects, or their products are used in the region, or, in one case (''Crocus sativus'' L.) because the product is commonly confused with products of indigenous plants.

			Many vegetable dyes and tannins are non timber products of the forest, just like resins, gums, and latex. The latter products are often used in paints and inks. Examples include "gum damars"" from species of Dipterocarpaceae and "karaya gum"" from the Indian ''Sterculia urens'' Roxb. They do not have colouring properties, but are sometimes used as a thickening agent in solutions of dyes. These products are not dealt with in this volume, but will be treated in the volume "Plants producing exudates"". Some exudates, however, have dyeing properties, e.g. the gum resin from ''Garcinia hanburyi'' Hook.f.; hence this species is treated in this volume.

	This volume deals with plants producing substances used as dye or tannin in South East Asia. Dyes and tannins are closely related. Certain plants (e.g. Phyllanthus emblica L.) contain substances that can be used for dyeing and others that can be used for tanning. As well as being used for tanning, tannins are often also used for dyeing or staining; for example, the dark coloured extract obtained by boiling chips of the heartwood of Acacia catechu (L.f.) Willd. known as "catechu"" is employed both for dyeing and for tanning. The basic components of many vegetable dyes are chemically comparable with those of tannins. For these reasons vegetable dyes and tannins have been dealt with together in one volume.
	The species (genera) described are primarily used as dye or tannin, and have some economic importance (at least locally). Mangrove species are perhaps primarily used locally for firewood, charcoal and timber, but because they play a major role in the tanning industry, they have also been included. Similarly, Phyllanthus emblica L. and Terminalia catappa L. have been included here, even though they are also important for their edible fruits. Some dye and tannin producing plants are poorly known. Their use is occasional and very local, and they have been classified as "dye and tannin producing plants"" because they have no other uses; most of these species are presented in this volume in Chapter 3 "Minor dye and tannin producing plants"".
	In some cases, plants that do not occur naturally or in cultivation in the Prosea region are described because they may have interesting prospects, or their products are used in the region, or, in one case (Crocus sativus L.) because the product is commonly confused with products of indigenous plants.
	Many vegetable dyes and tannins are non timber products of the forest, just like resins, gums, and latex. The latter products are often used in paints and inks. Examples include "gum damars"" from species of Dipterocarpaceae and "karaya gum"" from the Indian Sterculia urens Roxb. They do not have colouring properties, but are sometimes used as a thickening agent in solutions of dyes. These products are not dealt with in this volume, but will be treated in the volume "Plants producing exudates"". Some exudates, however, have dyeing properties, e.g. the gum resin from Garcinia hanburyi Hook.f.; hence this species is treated in this volume.
	Chapter 4 lists species that have another primary use and have been or will be dealt with in other volumes of the Prosea handbook. However, because of their importance as dyes or tannins in South East Asia, concise information is given in Table 1 (dyes) and Table 2 (tannins).		Chapter 4 lists species that have another primary use and have been or will be dealt with in other volumes of the Prosea handbook. However, because of their importance as dyes or tannins in South East Asia, concise information is given in Table 1 (dyes) and Table 2 (tannins).


	Table 1. Alphabetical list of important dye producing plants with another primary use. Scientific name, family name, vernacular name, part of the plant used for dyeing, colouring substance and colour, and material suited for dyeing are given, where known. See Chapter 4 for commodity group and synonyms.		Table 1. Alphabetical list of important dye producing plants with another primary use. Scientific name, family name, vernacular name, part of the plant used for dyeing, colouring substance and colour, and material suited for dyeing are given, where known. See Chapter 4 for commodity group and synonyms.
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	Anacardium occidentale (Anacardiaceae), cashew: bark and fruit used for the manufacture of marking ink and for colouring hair black.		*''Anacardium occidentale'' (Anacardiaceae), cashew: bark and fruit used for the manufacture of marking ink and for colouring hair black.
	Arcangelisia flava (Menispermaceae): stem, containing berberine, used for colouring cloth yellow.		*''Arcangelisia flava'' (Menispermaceae): stem, containing berberine, used for colouring cloth yellow.
	Archidendron pauciflorum (Leguminosae): bark used for dyeing matting black and fruit for dyeing silk purple.		*''Archidendron pauciflorum'' (Leguminosae): bark used for dyeing matting black and fruit for dyeing silk purple.
	Areca catechu (Palmae), betel nut palm: nuts used for dyeing cotton and wool red brown or black.		*''Areca catechu'' (Palmae), betel nut palm: nuts used for dyeing cotton and wool red brown or black.
	Artocarpus heterophyllus (Moraceae), jackfruit: heartwood, containing morin, used for dyeing cotton and silk cloth yellow.		*''Artocarpus heterophyllus'' (Moraceae), jackfruit: heartwood, containing morin, used for dyeing cotton and silk cloth yellow.
	Artocarpus integer (Moraceae), chempedak: heartwood used in the same way as for A. heterophyllus.		*''Artocarpus integer'' (Moraceae), chempedak: heartwood used in the same way as for ''A. heterophyllus''.
	Baccaurea javanica (Euphorbiaceae), menteng: bark used for dyeing cotton and linen cloth and cigar boxes yellow red or violet; also used as a mordant.		*''Baccaurea javanica'' (Euphorbiaceae), menteng: bark used for dyeing cotton and linen cloth and cigar boxes yellow red or violet; also used as a mordant.
	Baccaurea motleyana (Euphorbiaceae), rambai: bark used in the same way as for B. javanica.		*''Baccaurea motleyana'' (Euphorbiaceae), rambai: bark used in the same way as for ''B. javanica''.
	Baccaurea racemosa (Euphorbiaceae), kapundung: bark used in the same way as for B. javanica.		*''Baccaurea racemosa'' (Euphorbiaceae), kapundung: bark used in the same way as for ''B. javanica''.
	Bischofia javanica (Euphorbiaceae), red cedar: bark used for dyeing matting red or black.		*''Bischofia javanica'' (Euphorbiaceae), red cedar: bark used for dyeing matting red or black.
	Carthamus tinctorius (Compositae), safflower: flowers, containing carthamin, used for dyeing silk, cotton and linen cloth yellow red.		*''Carthamus tinctorius'' (Compositae), safflower: flowers, containing carthamin, used for dyeing silk, cotton and linen cloth yellow red.
	Clitoria ternatea (Leguminosae), cordofan pea: flowers used for dyeing food, matting and cloth blue green.		*''Clitoria ternatea'' (Leguminosae), cordofan pea: flowers used for dyeing food, matting and cloth blue green.
	Cocos nucifera (Palmae), coconut palm: nuts used for dyeing silk green, and fruit stalk used for colouring teeth black.		*''Cocos nucifera'' (Palmae), coconut palm: nuts used for dyeing silk green, and fruit stalk used for colouring teeth black.
	Curcuma longa (Zingiberaceae), turmeric: rhizome, containing curcumin, used for dyeing food, cotton and silk cloth, matting and parts of the skin yellow brown.		*''Curcuma longa'' (Zingiberaceae), turmeric: rhizome, containing curcumin, used for dyeing food, cotton and silk cloth, matting and parts of the skin yellow brown.
	Dracaena angustifolia (Liliaceae), suji: leaves used for colouring food green.		*''Dracaena angustifolia'' (Liliaceae), suji: leaves used for colouring food green.
	Flemingia grahamiana (Leguminosae): glands on the pod, containing flemingin, used for dyeing silk orange.		*''Flemingia grahamiana'' (Leguminosae): glands on the pod, containing flemingin, used for dyeing silk orange.
	Flemingia macrophylla (Leguminosae): glands on the pod used in the same way as for F. grahamiana.		*''Flemingia macrophylla'' (Leguminosae): glands on the pod used in the same way as for F. grahamiana.
	Garcinia atroviridis (Guttiferae): fruit used as a mordant in dyeing silk.		*''Garcinia atroviridis'' (Guttiferae): fruit used as a mordant in dyeing silk.
	Garcinia dulcis (Guttiferae): bark used for dyeing cloth and matting brown.		*''Garcinia dulcis'' (Guttiferae): bark used for dyeing cloth and matting brown.
	Garcinia mangostana (Guttiferae), mangosteen: fruit rind used for dyeing cloth brown black, bark for dyeing cloth yellow.		*''Garcinia mangostana'' (Guttiferae), mangosteen: fruit rind used for dyeing cloth brown black, bark for dyeing cloth yellow.
	Hibiscus rosa sinensis (Malvaceae), shoe flower: flowers used for colouring food red, and shoes and eyebrows black.		*''Hibiscus rosa-sinensis'' (Malvaceae), shoe flower: flowers used for colouring food red, and shoes and eyebrows black.
	Mangifera indica (Anacardiaceae), mango: bark used for dyeing cloth and matting yellow.		*''Mangifera indica'' (Anacardiaceae), mango: bark used for dyeing cloth and matting yellow.
	Melastoma malabathricum (Melastomataceae), senduduk: roots used in mixtures for dyeing red, leaves in mixtures for purple; fruits used for dyeing cloth black; ashes used as a mordant.		*''Melastoma malabathricum'' (Melastomataceae), senduduk: roots used in mixtures for dyeing red, leaves in mixtures for purple; fruits used for dyeing cloth black; ashes used as a mordant.
	Melastoma sanguineum (Melastomataceae): plant used in the same way as for M. malabathricum.		*''Melastoma sanguineum'' (Melastomataceae): plant used in the same way as for M. malabathricum.
	Psidium guajava (Myrtaceae), guava: leaves used in mixtures for dyeing silk and cotton cloth and matting black.		*''Psidium guajava'' (Myrtaceae), guava: leaves used in mixtures for dyeing silk and cotton cloth and matting black.
	Pterocarpus indicus (Leguminosae), red sandalwood: wood, containing santalin, used for dyeing cotton cloth, wool, leather, bamboo and other woods red.		*''Pterocarpus indicus'' (Leguminosae), red sandalwood: wood, containing santalin, used for dyeing cotton cloth, wool, leather, bamboo and other woods red.
	Pterocarpus santalinus (Leguminosae): wood used in the same way as for P. indicus.		*''Pterocarpus santalinus'' (Leguminosae): wood used in the same way as for P. indicus.
	Syzygium spp. (Myrtaceae): bark used for dyeing cotton cloth brown black.		*''Syzygium'' spp. (Myrtaceae): bark used for dyeing cotton cloth brown black.
	Tagetes erecta (Compositae), marigold: flowers, containing quercetagetin, used for dyeing silk and chicken food yellow.		*''Tagetes erecta'' (Compositae), marigold: flowers, containing quercetagetin, used for dyeing silk and chicken food yellow.
	Tagetes patula (Compositae), marigold: flowers used in the same way as for T. erecta.		*''Tagetes patula'' (Compositae), marigold: flowers used in the same way as for T. erecta.
	Tamarindus indica (Leguminosae), tamarind: fruit pulp used as a mordant.		*''Tamarindus indica'' (Leguminosae), tamarind: fruit pulp used as a mordant.
	Tectona grandis (Verbenacea), teak: root bark and leaves used for dyeing matting yellow-brown.		*''Tectona grandis'' (Verbenacea), teak: root bark and leaves used for dyeing matting yellow-brown.


	Table 2. Alphabetical list of important tannin producing plants with another primary use. Scientific name, family name, vernacular name, part of the plant used for tanning, percentage tannin on dry weight basis, and material suited for tanning are given, where known. See Chapter 4 for commodity group and synonyms.		Table 2. Alphabetical list of important tannin producing plants with another primary use. Scientific name, family name, vernacular name, part of the plant used for tanning, percentage tannin on dry weight basis, and material suited for tanning are given, where known. See Chapter 4 for commodity group and synonyms.