Lac

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Indian Lac and Asian lacquer are terms used interchangeably. They are both varnishes from natural sources; the former from insects that exude a glandular secretion while the latter the resin from the sap of a tree.

Contents

What is Lac

Lac is a sticky, resinous secretion of the tiny lac insect, Laccifer lacca, which is a species of scale insect.

The female insect, globular in form, lives on twigs and young branches in cells of resin created by exudations of lac. The most common trees this is found on are several varieties of soapberry and acacia trees and particularly on the sacred fig, Ficus religiosa, in India, Thailand, Myanmar (Burma), and elsewhere in Southeast Asia.

The lac is harvested predominantly for the production of shellac and lac dye, a red dye widely used in India and other Asian countries. Forms of lac, including shellac, are the only commercial resins of animal origin.


History and origin

It is rather difficult to fix a time and a place for the origin of Asian lacquer or the Indian one as it's use to coat objects predates written history. Very early examples have been excavated throughout asia. [1]

In China, excavations in Yuhao and Humendu have brought to the surface several red lacquer bowls from neolithic times. By the time of the Shang dynasty (16 to 11 Century B.C.) sophisticated painted designs excavated in Hebei province show that the production of lacquerware was already a highly developed art. From this period forward lacquer was commonly used to coat a variety of objects like musical instruments, weapons, coffins, furniture and other household items.

The development of Korean lacquer is contemporary with that of China as their histories are intertwined. The earliest example of lacquerware excavated in Korea is a group of lacquer-coated bronze vessels.

The first evidence of the use of lacquer in Japan appears during the Jomon period (4000 to 400 B.C.). In the Torihama mounda in Obama-shi Fukui prefecture, arrows, bowls, and combs, with lacquer coatings have been excavated.

Many pieces of European furniture were japanned or "lacquered" using Western shellac to simulate Asian lacquer, for which there was a high demand. These pieces of furniture were valued in their own right as they were intrinsically different from Asian lacquer, and gave rise to the generic use of the term "lacquer", to refer to any applied coating.

In India, lac, lacquer or shellac products have been used from as early as about 1200 B.C as plastic and decorative materials. During the 17th century, after traders had introduced lac dye and, later, shellac to Europe, lac became commercially important there.

The word lac is the English version of Persian and Hindi words that mean “hundred thousand,” indicating the large number of the minute insects required to produce lac. In fact, about 17,000 to 90,000 insects are needed to produce one pound of shellac.

The maximum yield of resin and dye is obtained by gathering stick lac (i.e., the twigs with their living inhabitants) in June and November. Lac dye is obtained from ground stick lac by extraction with hot water or hot sodium carbonate solution.

Seed lac is the resin, freed from the lac dye. After the seed lac is melted, strained through canvas, spread, cooled, and flaked, it becomes the shellac of commerce. The palest orange lac is the most valuable.

Sources

  • Raw lacquer is the sap from several species of trees within the Anacardiaceae family, genus Rhus. Most literature concerning lacquer mentions the source as the Rhus verniciflua while some still refers to the other name of Rhus vernicifera.
  • Other species of Rhus found throughout the world are the sumac and posion ivy. Many members of the Rhus contain urushiol in the sap, which is the active ingredient that polymerizes to form lacquer. The raw lacquer is a skin irritant, to which workers have to develop a tolerance.
  • Rhus verniciflua is the main tree used to produce raw lacquer in China, Japan and Korea, though there are a number of other trees in the far east that are also used.
  • The tree Melanorrhoea usitate is used in Burma and Thailand.
  • In Vietnam and Taiwan, sap is collected from Rhus succedanea, and in Indonesia Rhus javanica is used. In many of these trees there are a large number of other compounds found in the sap, which reduces the efficiency of the polymer reaction.
  • In addition to true lacquer there are a number of similar materials in use; Anacardium occidentale (cashew nut oil) is one of them. Although related to lacquer, this coating does not polymerize in the same manner and the coating is less durable.
  • Lacquer does not cure in the same way as other natural resins such as shellac, mastic or dammar. Unlike lacquer, these other natural resins are dissolved in a solvent, and when the mixture is applied as a coating, the resin hardens into a solid film as the solvent evaporates.

Harvesting

In most lacquer producing countries the sap is traditionally collected several times a year. The properties of the sap vary depending on the time and place it is collected. Recent studies show that the constituents change slightly throughout the year and therefore the working properties would change accordingly. In Japan, the harvest season begins in June. Late July through August is the most productive season for urushi due to the high temperature and moderate rainfall. This is used for black or clear top coating.

In China, the lacquer trees grow in mountainous regions of twenty three different provinces, with 161 recorded districts harvesting raw lacquer. China leads the world in production and export. In the warmer regions tapping begins in mid-june and continues till the first frost. In cooler areas, harvesting does not begin until mid-july and continues until mid-october.

Korea also grows and harvests lacquer from the Wonju area from Hune until mid-october.

Harvesting lacquer in Burma is slightly different. The trees, Melanorrhoea usitate, are much alrger and grow wild in mountainous regions and not in lacquer producing orchards. The sap is collected year round except in the months of January to March, when the flowering season occurs.

In Vietnam the harvesting is similar to Burma.

Production of lacquer objects

The production of lacquered objects is a painstaking process which involves many steps, and often a series of craftsmen. The fabrication of the substructure to which the lacquer is applied may fall to one artisan, the preparation of the ground layers to another, and the final decoration to yet another.

The Substructure

  • Objects are not made of solid lacquer; the liquid lacquer must be brushed onto a substructure which determines the shape of the object.
  • The form

The form can be made of wood, bamboo, cane, textile, leather, metal-- or any lightweight material. Generally, the substructure is constructed of seasoned wood, with any seams or holes filled with grout, the corners often reinforced with fabric, and rims and feet sometimes made of metal wire. The substructure may be primed with ground layers (urushi mixed with clay) until it is smooth and without any flaws which would disrupt the lacquer coating.

  • Applying the lacquer

The lacquer is applied to the substructure in very thin layers, and after each layer cures in a humid, dust-free cabinet for a day or longer, it is then polished and another layer is applied; an object may have only a few or more than a hundred layers, progressing to a very refined final lacquer surface.

  • Varnish and Colours

The lacquer may be used in a transparent state, as a "varnish" over bare wood, or it may be opaque and colored by the addition of mineral pigments. Cinnabar and iron oxide were used to make red and black lacquers, orpiment for yellow lacquer. Until the development of synthetic colors, white, blue and green were not used, as these natural pigments are unstable in lacquer. Oils and other ingredients were added as dictated by various recipes; these are sometimes blamed for a lacquer which peels, lacks a uniform color, or performs poorly in some other way.

  • Dry lacquer

In a technique called dry lacquer, used to make religious statues, fabric saturated with lacquer is molded or modelled-- somewhat like papier mache -- over a wood or clay core. Once the latter is removed, the resulting sculpture is hollow, with perhaps a wood frame or armature added for strength.

Decoration of lacquer Utilitarian objects were generally monochrome and left undecorated, although there are examples where layers of alternating colors were used, so that with wear, the black layer would gradually reveal a red underlayer, or vice versa. Alternating layers of colors were sometimes also used in lacquer that was to be carved, so that the angled incisions reveal the multi-colored striations, confirming the number of layers. The finest of these Chinese lacquers required many layers to create such depth, and were sometimes so deeply carved that sections of the design have a tendency to separate from the substructure. Cheap imitations consist of a few coats of lacquer applied to previously carved wood or molded rubber.

  • Lacquer Decoration

Lacquer can be decorated by laying pieces of mother-of-pearl, metal cut-outs, tortoise shell and many other materials in the lacquer; layers of lacquer might be applied over them, and the surface polished back down to reveal the decoration.

What is Japanese lacquerware

South and Southeast Asian lacquerware is very different to Japanese lacquerware. After the sap has been removed from the urushi tree, it is aged for from three to five years and then processed to form a number of lacquer types with different properties.

Urushi is applied as a thin coating over a usually wooden core. After this process it undergoes a chemical hardening process (very different from evaporative drying) in conditions of high humidity and temperature. The hardened urushi coating repels water and resists acid, alkali, salt, and alcohol. It even insulates against heat and electricity.

Urushi contains urushiol (the same as found in poison oak and ivy), which is responsible for lacquer's wonderful material properties as well as giving some people a month or so of severe itching if liquid urushi is touched.

The impervious yet resilient surface, a surface that is terribly strong yet soft to the touch, has given lacquer ware its appeal over the millennia. [2]

The Japanese achieved brilliant effects with the use of metal powders, a technique known as makie, or sprinkled picture. Here selected grades of powdered and flattened metal are dusted or painstakingly positioned onto the wet lacquer, to create background effects, or a detailed composition. Entire surfaces are sometimes gilded in this way, and tend to be easily scratched and abraded.

Lacquer is also used as a feature of Coromandel screens; here the wood substructure is coated with a heavy layer of white chalk, and then the entire surface is lacquered. Shapes are cut into the lacquer surface to reveal the white layer, which is then painted using a variety of colors.

Japansese lacquerware includes writing cases, paperweights, furniture, goblets, jewellery boxes, bowls etc. The designs are of typical Japanese asymmetrical simplicity.

Did you know

  • The ancient India, red lac and betel leaf juice were used as lipsticks as well as decorative stains for women's palms.

Lac in India

The trade in lac is unusual in that a majority of the product (75% of the toal in India as a whole) is exported to countries including the USA, UK, Germany, Singapore, Italy, Indonesia, Egypt, and New Zealand. Bihar is the major producer of lac in India (over 55% of the total), followed by Madhya Pradesh, West Bengal and Uttar Pradesh. Orissa is not a major producer of lac.

  • Lac host trees in India

The main lac hosts in Bihar are Palas (Butea monosperma), Ber (Zizyphus jujuba) and Kusum (Schleichera oleorosa). In some of the areas, lac collection seems to be the only source of income for the tribals living in the area.

Traditional Communities that work with Lac

  • India

Lakhera or Lakheri is a community migrated from Marwar or Rajputana in North western India and settled in some areas of Maharashtra. This community has derived it's name Lakhera or Lakheri from Lakh or Lac. They are the makers of the lac bangles and some other articles from lac or lacquer.

  • Western Yunnan, Southwest China

The lacquer tree (Toxicodendron vernicifiuum) based agroforestry system is a very important farming system with development potential in western Yunnan, southwest China. The Lemo people (a branch of the Bai minority nationality) traditionally grow lacquer trees interplanted with upland food crops in swidden (alash and burn or shifting cultivation)fields. In the 10 to 15 year period when the fields are left fallow, farmers harvest various products from lacquer trees, including resin for selling or trading, leafy shoots for vegetable, pericarps for making wax, roots and leaves for pesticide, dry resin for medicine, and seeds for vegetable oil extraction.[3]

Uses of Lac

Indian Stick lac as well as Asian lacquer has traditionally been used as glue to make or repair farm equipment, connecting between iron part and wooden part. It has also been widely used for dyeing silk and cotton. There is a significant demand in the international market for high quality lac. The processing plant would cater to the following target market.

  • Adhesive industry
  • Food processing and beverages
  • Varnish and printing
  • Pharmaceuticals and cosmetics
  • Textiles
  • Leather, electrical and polishes

Problems Lac Cultivators Face

  • Lack of adequate processing facilities

The absence of adequate processing facilities, makes lac cultivators unable to realize the full value of their product. This is because the market value of crude lac is rather limited in comparison to the final processed products such as Shellac which commands a premium in the market.

  • Inefficient extraction method

The lac dye is isolated during the processing and is a valuable product for the textile industry as a colouring agent. The pigment content of the sticklac can be as high as 10% but the yield of isolated lac dye usually is less than 1% due to the inefficient extraction method.

Recent research

  • Recent research shows that the resin from certain lacquer trees like the Thai and the Japanese causes contact dermatitis. The causative agent, the resin, induces either irritation or sensitization. [4]

Cleaning and maintaining lacquerware

  • Keep out of direct sunlight and away from extreme heat. Ultraviolet light and extreme heat will fade the surface of the lacquer ware and allow fine cracks to form. Once light or heat damage has occurred, other deterioration can happen as well, and the beauty and life-span of your product will be reduced.
  • Do not use any chemicals to clean a lacquerware product. Instead, use a dry or damp cloth to gently wipe it down. This should be done routinely as dirt or moisture may build up if your product is used often.
  • When using lacquerware with food, it can be cleaned with mild soap and warm water. Rinse and dry immediately after cleaning. Do not soak or use hot water to clean your product.
  • Lacquer products are susceptible to damage from very dry conditions or fluctuating humidity. A climate that is between 60% and 70 % humidity is recommended to ensure it's long life.
  • Although lacquer is prized for its durable nature, it can be scratched with, for example, Western silverware, with which it was not meant to be used.
  • As the substructure is usually very lightweight, placing heavy items in or on lacquerware can result in structural damage.
  • It is better to use the Asian technique of urushi repair and restore lacquer.
  • Lacquer which is travelling should be sent in secure crates and provided with plenty of packing materials to absorb shocks, but also to buffer changes in relative humidity (RH). Silica gel and Artsorb can also be used to maintain a constant RH. When the piece arrives at its destination, it should be left in its packing for as long as possible to allow it to acclimatize to its new environment, and only slowly exposed to the new conditions.

References

  • How Stuff Works
  • Lac in Madhya Pradesh
  • Lac Craft in India
  • How to get the cracked lacquer effect
  • Lacquerware at Wikipedia
  • Lac production and development in Vietnam
  • Bengal Lac
  • Traditional Crafts of Japan
  • Non Timber Forest Products: Availability, Production, Consumption, Management and Marketing in Eastern India by Mitchell, Corbridge, Jewitt, Mahapatra, Kumar, April 2003
  • Lacquer Work
  • Lacquer: Technology and Conservation Lacquer: (Conservation and Museology Series)by Marianne Webb, Butterworth-Heinemann (March 13, 2000)
  • Burmese Lacquerware (Paperback)by Sylvia Fraser-Lu, Orchid Press; Rev Exp edition (2000)
  • For the Love of Lacquer. The Museum Fur Lackkunst in Munster

See Also