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Rasayana Shastra (रसायनशास्त्रम्) (view source)
Revision as of 00:08, 18 April 2020
, 00:08, 18 April 2020→Traditional Chemical Practices in India: added pottery and glass with references
# Fermentation Technology
# Fermentation Technology
# Extraction of Oils: Perfumes for cosmetics and consumption
# Extraction of Oils: Perfumes for cosmetics and consumption
# Dyeing: Numerous dyes from vegetable and mineral sources
# Dyeing: Numerous dyes from vegetable and mineral sources, use of mordants for textiles, craft paints
# Glass
# Glass
Information about Ayurvedic medicinal preparations, and of mercurial preparations is available in [[Rasashastra (रसशास्त्रम्)|Rasashastra]] and [[Rasayana (रसायनम्)|Rasayana]] under Ayurveda category.
=== Pottery - Preparation and Painting ===
Pottery and pottery-painting were practised in India ever since the dawn of civilisation. People in very ancient settlements were well-acquainted with the art of making potteries of burnt clay and painting various designs on them. A large variety of ochres, haematites, pigments and organic colours were used by potters for painting the pots. This art of using pigments for beautification of pottery led to the development of paint technology in India.
Archaeological evidences of pre-historic settlements unearthed in various parts of India have revealed a large number of earthen ware items implying that the inhabitants of these early settlements were well-acquainted with the techniques related to pottery making, dye preparation and painting. It is interesting to note that regarding the pre-historic cultures, archaeologists have given a broad classification as Buff-ware culture and Red-ware culture based on the colours of the potteries distinctively found in those settlements. Potters' wheel was the characteristic implement of the Indus valley civilization.<ref name=":12">Krishnamurthy. Radha, (1997) ''History of Technology in India, Vol. 1, From Antiquity to c. 1200 A.D.'' New Delhi: Indian National Science Academy. (Chapter Dyes, Mordants and Pigments: Pages 309 - 312)</ref>
The characteristic ‘red and black’ pottery of Harappan civilization and a few polychrome potteries that have also been unearthed in these sites are painted in green and red on a buff slip. Chemical analysis revealed that red or Solomon colours in these objects are due to the presence of iron components in the clay. The slip of bright red colour is due to ferric oxide. The black and chocolate designs that are found painted on the body of the pottery owe their colour to oxides of manganese. The colouring agents used by the Indus valley people are used even today by potters. Many of the ancient techniques of selecting and applying colouring materials have come down to the present time also.<ref name=":12" />
Slip treatment was given to the pots before they were fired. Slipping serves two purposes it helps in closing the pores and provides smooth surfaces helpful in painting a design on them. Slipping was done by dipping the pot after burnishing in a solution or by painting with a solution formed by the finest portion of the clay used for making the pot or of any suitable materials such as ochres, pigments.
It is important to note that knowledge of colors and causal components were well known to the people. It is significant that the colors of these slips neither vanish nor fade in firing.
* Light pink shades - traces of iron in clay
* Dark pink - addition of red ochre in clay or as a slip directly
* Dark red - red oxide added to slip
* Yellow - addition of yellow ochre
Black and chocolate shades - manganiferous hematite was used (in combination if manganese is more produces pure back color, if iron preponderates it gives a chocolate color)
The technique of painting pots before firing and also painting designs on them after firing was in vogue. Mostly organic colours were used to paint the surfaces. For white pigment, lime, limestone, chalk and rice powder were used. To prepare black pigment, burnt coconut shell powder, soot, powdered charcoal, black iron oxide etc. were found to be used in some other settlements.
During Vedic times and later on, ritual pots were painted with floral and geometrical designs in red, yellow blue and green colours. The solvent used for these pigments was plain water.
* Vermilion (mercuric sulphide) or dhau (ruddle) was used from red pigment
* Turmeric and yellow ochre was used for yellow colour
* Blue from indigo
* Green from leaves of particular trees and iron sulphate
* Grey was prepared from a kind of haematite
* Orange pigments were obtained by mixing red and yellow colours
* Copper sulphate was mixed with red pigment to obtain purple pigment
It is evident that methods like filtration, decantation, making pastes by rubbing on granite with little water, boiling with ingredients like calcium, catechu, soda etc, plant identification and collection of barks and leaves, and fermentation using rice starch were the adopted chemical processing techniques in preparation of pigments.<ref name=":12" />
=== Tinted Glass ===
Manufacture of glass and coloured glass is well documented in ancient literature such as Ramayana (2.90.27) (and other Jain texts), even though no glass objects have been recovered from Indus valley areas. Kautilya in his Arthashastra while laying down rules for the Superintendent of the treasury talks about the identification of various kinds of gems and precious stones and mentions a few times about glass; in the context of testing gems to place them in jewelry, in trade and tax payments, robbery and fines.<ref>Krishnamurthy. Radha, (1997) ''History of Technology in India, Vol. 1, From Antiquity to c. 1200 A.D.'' New Delhi: Indian National Science Academy. (Chapter Dyes, Mordants and Pigments: Pages 312)</ref>
* शेषाः काच-मणयः ।। ०२.११.३६ ।। (Arth. Shas. 2.11.36)<ref>Arthashastra ([https://sa.wikisource.org/wiki/%E0%A4%85%E0%A4%B0%E0%A5%8D%E0%A4%A5%E0%A4%B6%E0%A4%BE%E0%A4%B8%E0%A5%8D%E0%A4%A4%E0%A5%8D%E0%A4%B0%E0%A4%AE%E0%A5%8D/%E0%A4%85%E0%A4%A7%E0%A4%BF%E0%A4%95%E0%A4%B0%E0%A4%A3%E0%A4%AE%E0%A5%8D_%E0%A5%A8/%E0%A4%85%E0%A4%A7%E0%A Adhikarana 2 Adhyaya 11])</ref> rest are the glass gems.
* क्षेपणः काच-अर्पण-आदीनि ।। ०२.१३.३८ ।। (Arth. Shas. 2.13.38)<ref>Arthashastra ([https://sa.wikisource.org/wiki/%E0%A4%85%E0%A4%B0%E0%A5%8D%E0%A4%A5%E0%A4%B6%E0%A4%BE%E0%A4%B8%E0%A5%8D%E0%A4%A4%E0%A5%8D%E0%A4%B0%E0%A4%AE%E0%A5%8D/%E0%A4%85%E0%A4%A7%E0%A4%BF%E0%A4%95%E0%A4%B0%E0%A4%A3%E0%A4%AE%E0%A5%8D_%E0%A5%A8/%E0%A4%85%E0%A4%A7%E0%A Adhikarana 2 Adhyaya 13])</ref> Kshepana, guna, and kshudra ate three kinds of ornamental work. Setting jewels (kácha, glass bead) in gold is termed kshepana.<ref>Shamasastry. R, ''Kautilya's Arthashastra with English Translation'' (Page 120)</ref>
* Evidence of trade of glass items<ref>Shamasastry. R, ''Kautilya's Arthashastra with English Translation'' (Page 343)</ref>
Archaeological evidences support the use of glass beads, bangles, jars, tiles etc. made from 6th or 5th century' B.C. onwards. Most of the glass objects were coloured. Glass manufacture practiced as an indigenous industry in ancient India is seen in excavations particularly in the south (Arikamedu, Uraiyur). Along with this, the technique of colouring glass also developed. The glass specimens show that the glass makers of ancient India were highly competent in giving different colours and shades to glass objects.
Chemical analysis revealed, just like in the case of pottery, that colouring agents were obtained from the metallic ores. Different chemicals added to them finally led to attribute different shades of colours and glazes to the glass objects. Coloured glass was prepared by mixing silicates of soda, lime and appropriate metallic oxides (Jaggi, I p.203). Copper oxide, iron oxide, manganese oxides were generally used to give colours to the glass articles as for pottery. A special type of glass beads of 350 A.D. to 750 A.D. found at Ahicchatra is of gold foil glass. Layers of gold foils were poured in between two glass layers. All these prove that craftsmen in ancient India were highly skillful in the sophisticated technique of using metallic ores and chemicals as pigments in colouring very high temperature melting media like glass.
== References ==
== References ==
[[Category:Shastras]]
[[Category:Shastras]]
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