As appreciation of Chola Bronzes has grown among museums and collectors, prices at auction for originals with a solid provenance are fetching millions. Chola Bronzes in their hundreds, perhaps thousands, were buried during the Mughal invasions of the 14th century and when they are re-discovered, come onto the open market through legal channels, or otherwise. While reputable auction houses vet the provenance of Chola originals, many thousands are being stolen to order from village temples and shrines where they have sat unguarded, their custodians unaware of their icon’s material value in the secular world.
In recent years there have been several high profile cases involving major art dealers discovered dealing in stolen Chola Bronzes. Their clients, otherwise reputable museums and galleries, obliged to return to India pieces purchased in good faith. Meanwhile enforcement at the source remains largely ineffectual.
Shailja and I hope museum quality reproductions such as ours will go in some small way towards satisfying collectors so originals may continue being venerated in their temples where they belong. The quality of our pieces creates a problem, however, when it’s not uncommon for fine art reproductions such as ours to be surreptitiously exchanged for temple originals. To preclude our pieces being used in this nefarious trade we subtly cast into the rear of the base the Mantra name, unalterable evidence of their provenance as 21st century Chola Bronzes.
Gods Forsaken – The Illegal Trade in India’s Sacred ArtTerry Curell2019-11-08T10:24:51-08:00
The aesthetic achievements of the Chola bronzesmiths are plain to see, yet the sophistication of their casting process is also impressive.
A thousand years ago, Chola craftsmen had reached a level of technical sophistication equalled only today using state of the art materials and techniques. As a result, the beauty of their Chola Bronzes remain undimmed by time, a remarkable achievement given that many museum pieces have been buried for hundreds of years (note 1).
Chola Bronzes were, and are to this day, created using the traditional lost wax, or cire perdu, process, a technique which has been used for thousands of years. The process begins by modelling a maquette, or full size model, of the figure in wax mixed with resin from the Oriental Plane tree and ground nut oil (four parts wax, four parts resin and one part oil). The wax figure is then coated with three consecutive layers of clay; the first coat is very fine and thin, about 3 mm, made from silt collected from the banks of the Kaveri River mixed with finely ground burnt coconut husks and cow dung, the second layer is field clay mixed with sand, and the third layer a mix of coarse sand and clay. After drying in the sun for a few days and wrapped in wire for reinforcement, the wax/clay is heated over hot coals until the wax figure melts, or lost, out of the mould. Molten copper alloy is then poured into the void and solidifies as it cools. Breaking the clay open reveals the rough casting, but destroys the mould, rendering each bronze icon entirely unique.
With all the resources of the empire at their disposal Chola bronzesmiths developed significant improvements to the lost wax process and their descendants kept this arcane knowledge a closely guarded secret for almost a thousand years. Recent laboratory analyses, however, has revealed the formula for their alloy (note 2). In addition to the usual copper and tin, the presence of iron, silver and gold ensured their formula conformed to the Shilpa Shastra’s accepted definition of panchaloha, literally ‘five’ ‘metal,’ the auspicious bronze alloy used to create sacred icons (note 3).
Anyone who has ever experienced a Chola Bronze knows the bronzesmiths who created them were master craftsmen, however, they were limited by their technology. Theirs is a very impressive achievement when they were using river mud, beeswax, charcoal and cow dung. Today we have the advantage of computer-controlled, electric furnaces and certified pure bronze alloys to ensure a technical quality Chola bronzesmiths could only dream of achieving.
There is an undeniable charm to knowing your sculpture was created the old traditional way, but we feel any sculpture associated with gods and goddesses ought to be of the highest possible aesthetic and technical quality. Even if they are never used in spiritual practice, Chola Bronzes are by definition, sacred sculpture and deserve an appropriate level of care in their creation.
Note 1 – After the collapse of the Chola Dynasty, south India was spared the degree of depredation Mughal invaders inflicted upon Hindu temples and art in north India. When the Mughals arrived in the former Chola homeland in 1311 their touch was relatively light and they stayed for only a hundred years rather than the thousand years in the north. The brevity of Mughal occupation ensured Vedic Hinduism in south India remained relatively untouched and its temples remain as they were built a millennia or more ago. Light touch or not, the Mughals were offended by these voluptuously sensual bronzes and many were melted down into cannon. Fortunately for us however, temple priests of the time secretly buried their icons underground or hid them deep in their vaults. From time to time a hoard is found but the pieces are considered unconsecrated and therefore spiritually without value. While a precious few are reconsecrated and returned to their temples, most are acquired by museums or private collectors through legal channel – or otherwise.
Note 2 – in 2015, a metallurgical analysis of 130 original Chola Bronzes revealed that secret recipe to be; 82% copper, 7.7% lead, 7.1% tin, 0.51% iron, 0.16 % silver and 0.01% gold, as well as traces of several other elements. Reference; “Tamil Chola Bronzes and Swamimalai Legacy: Metal Sources and Archaeotechnology” by Sharada Srinivasan, Ph.D. The Journal of The Minerals, Metals & Materials Society (TMS) August 2016, Volume 68, Issue 8, pp 2207–2221.
Note 3 – A bronze cast using panchaloha was considered auspicious because, in the words of the renowned Chola expert, Dr. R. Nagaswamy, “In the south five metals were used, with copper being the base. These five metals, called panchaloha, were symbolically associated with the five basic elements, earth, water, fire, air, and ether. According to tradition, all physical bodies, including humans’, are composed of these five elements in different proportions. The sacred metal image, being the body of the Divine on earth, is thus also made up of the five elements that are represented by the metals.” (Nagaswamy, Timeless Delight, p. 13).
It is no longer possible in the West for panchaloha to be used when reproducing Chola icons due to its Pb (lead) content. Environmental, as well as health and safety concerns for foundry workers, must take precedence. Caution; Pb (lead) remains a major element for casting reproductions overseas. If you currently have Indian-sourced sculptures in your home please ensure your wax coating covers the entire surface and reapply it annually.
For thousands of years, bronze’s rich warm patina has made it the fine art sculptor’s preferred medium. Its beauty is more than skin deep, however; the moment freshly cast bronze is exposed to the atmosphere, carbon dioxide begins to react chemically with the copper, creating a micron-thin airtight barrier against the corrosive effects of further oxidation (note 1).
Colour can be any tone from light green to dark brown to mahogany to black, depending upon the purity of the alloy composition and its atmospheric environment. (For example, in Victorian London, monuments erected in public places became blackened due to sulphuric acid in the coal smoke).
Final colouration may take decades to reach maturity, however, the creation of a custom patina is completed in a matter of days by our expert patineurs (note 2).
When casting sacred sculpture, Chola bronzesmiths used the highest quality bronze alloy their technology allowed. A thousand years later we feel the same commitment and prefer to use Everdur, a premium sculptural bronze (95% copper, 4% silicon and 1% manganese). Everdur is formulated for purity, strength and predictable patination, whether faux or natural.
Panchaloha, literally “five metals’ was traditionally composed of 8 portions of copper, 8 portions of brass (an alloy of copper and zinc), 4 portions of silver, 1 portion of gold, and a small amount of iron. The formula was deemed auspicious and in the distant past was used extensively when casting sacred sculpture and much later, jewelry. Today’s panchaloha, while still containing some small portion of copper and brass, substitutes lead for silver and gold. Unfortunately, the term is used to describe almost any metal object exported from India associated with spirituality, trading on panchaloha’s ancient prestige to market inexpensive metal objects of poor quality.
Regardless of which protection you choose, your sculpture will need cleaning from time to time. We recommend you dedicate cleaning tools and material for use exclusively on your sculpture. Residue from brushes and cloths used for any other purpose may chemically react with the bronze. To prevent scratches when dusting with a brush, we recommend applying a protective layer of tape around your brush’s metal ferrules.
If your sculpture is installed outdoors, in the spring and fall wash with very mild soap and a soft brush, rinse thoroughly with tap water to remove all soap residue and allow to dry completely. This is an excellent time to apply a fresh wax layer, as even mild soap will strip old wax. Never use cleaning sprays or furniture polishes. They often contain chemicals which chemically react with elements within the bronze.
To wax or not to wax is a matter of personal preference. Unwaxed bronze’s colour will age naturally from a warm, bright shine to shades of black, red or pale green, depending upon the proportions of copper, tin or lead in the alloy. If at any point, you wish to preserve the current colour of your patina, applying a coat of wax acts as a barrier to further oxidation. In a dry climate, waxing once a year is sufficient; twice a year in areas of high humidity. If your sculpture is outdoors, it requires two coats. In any case, we recommend applying was outdoors at the height of summer, when the heat ensures the wax is absorbed deep into the pores. We also recommend using a premium clear paste wax such as Renaissance micro-crystalline wax polish, available from either; Picreator Enterprises Ltd http://www.sculpturedepot.net/clay-wax-tools/product.asp?Patina_Sealers, or Amazon.
An alternative to wax alone that’s been gaining popularity in recent years is a base coat application of a lacquer specially formulated for bronze sculpture. It comes in gloss or matte finish and has the advantage of permanent, thorough protection from oxidation, as well as oils from handling, from moisture, and even ultraviolet radiation. The disadvantage to lacquer is that it will ‘freeze’ its current patina colouration. These products are known as patina sealers and available from the same sculptor’s supply stores as the waxes.
When cleaning an older bronze, remember the patina is only a micron or two in thickness, so delicately apply just the thinnest wax coating. Ideally avoid polishing, handling or rubbing altogether.
When bronze is protected by its patina it is one of the most durable of metals. A pair of Greek bronzes, The Riace Warriors, were found on the Mediterranean seabed where they’d lain for over 2500 years https://en.wikipedia.org/wiki/Riace_bronzes. The high quality of the bronze alloy used in their casting ensured their patina protected them.
Ideally, patina covers the surface of a sculpture more or less uniformly and its lovely colouration is permanent protection against heat, humidity and atmospheric pollutants. However, if the bronze alloy or the casting is of poor quality, the oxidation process may spread beneath pitting and other surface imperfections to produce acid (normally hydrochloric or hydrosulfuric acid) which eats deeper into the bronze. Bronze Disease may initially present as a small furry ‘bloom’ of bright green or turquoise and may spread to other nearby bronzes.
Unfortunately, there is no permanent cure for the disease and many methods only halt the spread for a time until the metal and air interact again. Various treatments, such as baking at high temperatures, soaking in distilled water, and application of chemicals such as benzotriazole (BTA) are treatments. The course we recommend is to remove as much of the loose bloom as possible with a wooden implement to avoid damaging the patina surrounding the area, heating the affected area with a blow dryer or direct sunlight and finally, an application of either a premium clear paste wax such as Renaissance, or a specialty lacquer (see above). The goal here is to maintain an impermeable barrier between the atmosphere and the metal, a barrier that should be renewed regularly to avoid re-occurence.
Note 1 – this layer is two to three thousandth of an inch in thickness, or 0.05 to 0.07 mm.
Note 2 – it’s a time-honoured practice. The lustrous red-gold patinas of Italian Renaissance bronzes are the result of a coat of special lacquer.
Patina, Maintenance and Bronze Diseaseradarhill2019-11-08T09:05:57-08:00