ANNE BULMER BREWER STUDIO, Goldsmith & Artist

PRIMARY TECHNIQUES

Kum-Boo with 24K Gold

Japanese Patina

ADDITIONAL TECHNIQUES

KUM-BOO

Kum-Boo (also spelled keum-boo or kum-bu) is a Korean decorative appliqué technique in which pure gold foil is fused onto the surface of finished silver objects; similar techniques are also widely used in Japanese and Chinese metalwork. In the West, the method has more often been employed to fuse gold to iron, steel or copper. This technique can also serve to adhere 24k gold to gold, other standard colored-gold alloys, palladium, white gold and platinum.

The origin and historical development of the kum-boo technique are little known, but it is clear that Koreans have been using brass, silver, and gold ware and utensils for their daily eating and ceremonial purposes for thousands of years.

In the history of Korea, metal utensils and tableware, especially those made of silver and gold, had practical as well as aesthetic functions. Among the wealthy upper classes, silver tableware displayed status, but it also served the more practical purpose of testing food for spoilage or poison—a precaution used in the royal families for centuries.

Koreans and other East Asian peoples traditionally believed that the ingestion of pure gold would improve health and well-being. For this reason, many Korean silver utensils are decorated with 24-karat gold overlays in the form of letters and patterns that convey wishes for good health, wealth and longevity. In most cases, the ornament is set in the interior of a cup or bowl or within the bowl of a spoon, so that the food will be in contact with the gold and therefore able to assimilate its positive characteristics before being imbibed. For the same reason, many herbal medicines are covered in gold foil, and acupuncture needles are often made of a high-karat gold in the belief that the properties of this metal will enhance the efficacy of the treatment

JAPANESE PATINA

The fine metalwork of Japan has rarely been equaled. 

One of the things that makes Japanese metalwork so unique is the rich color pallet that is achieved by the use of patinas (a chemical process that alters the surface of the metal leaving a colored compound adhered to the metal). The rich history of Japanese patinas is the result of hundreds of years of experimentation, innovation and tradition.

Though the history of metalworking is relatively young in Japan, craftsmen there developed alloys and the art of patination further than any other metalworking culture in the world.

The Japanese patinas used by Anne Bulmer Brewer in her collections are selected because of their structural depth and strength - this means the patinas will hold their color and strength over time and wear. Anne has performed numerous tests with each patina used in her collections to ensure the integrity and last of each color.

The last stage in metalwork production is patination, a process crucial to the final appearance of a work. Patination is essentially a matter of oxidising the metal surface. Once the desired effect has been achieved, the object is covered with wax or urushi lacquer to prevent further oxidation and stabilise the colour obtained.

Countless patination techniques have been devised over the centuries, making up a body of inherited skills referred to as the 'secret teachings' of metalwork. One such technique, for example, involves the intentional corrosion of a cast iron surface by the application of an oxidising compound followed by heating, cleaning and the polishing on of urushi lacquer, which is hardened by firing to about 150�Ž (yakitsuke).

In the case of objects made of non-ferrous metals, the completed work is soaked in a solution of verdigris mixed with copper sulphate heated to 80�Ž. Once the desired colour has been obtained, the work is removed from the patinating solution, rinsed and then, by way of protection, treated all over with ibota-ro, a kind of insect wax.