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Tuesday, February 28, 2017

Collections Care Workshop Part IV
Putting the Gilt in Gilded Age: Exploring the Techniques of Ormolu, Urushi and Gilding

During June 2016, aspiring conservators from around the country attended a 2 week intensive workshop at Staatsburgh.  "Housekeeping for Conservators", sponsored by The Foundation for the American Institute for Conservation along with funding from the National Endowment for the Humanities taught in-depth methods of caring for many different types of collections. Participants gained insight into artifact conservation and the conditions that cause deterioration. After the workshop, several of the participants wrote blog entries about their experience and a specific aspect of the workshop.

NYS Bureau of Historic Sites Furniture Conservator, David Bayne, organized this workshop to occur at Staatsburgh collaborating on its organization with Independent Conservator Cathy MacKenzie and Kirsten Schoonmaker from the Shelburne Museum.  Several conservation experts also participated in the workshop's instruction including John Childs from the Peabody Essex Museum, Genevieve Bieniosek from the Biltmore, and Catherine Coueignoux London of Oak Street Conservation.

Part IV in this series of blogs is by Fallon Murphy. Fallon is from Redding, Connecticut and graduated from the University of Pennsylvania with a degree in sculpture in 2016. Throughout college, she has worked for several conservators, ranging from paper to sculpture. She recently completed a project on the Capitol Dome Project in Washington D.C. Currently, she is working at Harvard's Peabody Museum of Archaeology and Ethnology as a Conservation Lab Assistant; at Studio TKM on Chinese wallpaper, and for the Cambridge Arts Council studying graffiti removal.

Workshop participant and blog author, Fallon Murphy

When we were given the tour of the Mills’ mansion, it was incredible to see how decorated the house was. Coming from Philadelphia to the Conservation Workshop, it was surprising to see; I had only seen rooms like this when I looked through large architectural books.

The amount of gold utilized was particularly striking. Gold lined the spaces between the walls and the ceiling, it served as large frames for hanging textiles and it ornamented vases. With the amount of objects within the home, Mrs. Mills’ housekeepers, we might envision, were probably unbelievably busy. Within the mansion, the family hosted numerous people and had several parties. However, they had many homes and the house lay unused, with the shutters drawn, for a large portion of the year.

The purpose of the workshop was preventive conservation; in other words, instead of trying to fix an object that was broken, we tried to learn how objects deteriorate over time and what environmental factors cause an object to deteriorate faster. A good preventive conservation plan can help prevent larger disasters like an object breaking, a bug infestation, or an object being over exposed to light.

The work that the busy maids at Staatsburgh must have done daily is very similar to the planning and work that we did. Like one would expect of a housekeeper, we did a lot of dusting. Dust not only makes viewing objects difficult but it contains little pieces of hair and skin, making it scrumptious for some bugs. The removal of dust is pest management in a lot of ways. However, in contrast to the maids, who were probably focused on making the mansion appear new, we had to consciously move and dust with the intent to preserve the history of the rooms.

Several lectures focused on the gold that surrounds the walls at Staatsburgh and lines a lot of the objects. Instead of approaching each object with gold on it in the same way, we learned different techniques depending on how each object was made. The techniques that are exhibited in Mills’ home are called ormolu, urushi and gilding.


Ormolu is alternatively called gilt bronze, although this term is misleading; ormolu is typically gold adhered to brass or bronze.[1] Although this technique was known since antiquity, the development of ormolu was at its peak in the 18th and 19th century. Dating this type of work is difficult because it is seldom signed and typically reworked when the gold fades. What can help us date the process was a crowned C mark that the French stamped on many pieces. This was instituted from February 1745 to February 1749 for copper over a certain weight and gives us a sense of when ormolu was in its peak.[2]

All three items in the image have the ormolu technique: (l-r) the potpourri bowl, the clock and the fireplace mount.
The way an artisan prepares the gold for ormolu is through grinding gold leaf (moulu in French means powdered gold) together with mercury, forming a gray colored liquid with the consistency of putty. This paste is painted on a metal substrate and heated in a hot coal fire.[3] The mercury volatilizes and was very toxic for the craftsman.  In fact, mercury poisoning became so common from this practice that in 1778, the Society of the Arts (later the Royal Academy of the Arts) offered a prize for ways to control mercury poisoning from ormolu manufacture. After the heating, the gold remaining on the surface is polished by rubbing it with a hard smooth stone and completing further surface treatments.

Participant Allison Kelley puts an ormolu mount on the bureau drawer.

Although we did not do any cleaning of ormolu pieces, we handled the objects and learned about methods for preserving them. One housekeeping issue for ormolu is over polishing with abrasives. Polishing was done by the housekeepers in an attempt to keep the gold surface shiny. However, if it is done repeatedly, the gold will wear off.  The oils of people’s fingerprints and high relative humidity also negatively impact ormolu pieces.


Urushi and other Asian objects were very popular decorative items in European and American homes throughout the 18th and 19th century. The technique of urushi was so revered by Americans that they developed a technique that seems to imitate it.

Urushi comes from sap in a tree found in Japan, Southern China and Korea. To become a traditional urushi master in Japan, it typically takes eight years of apprenticeship. [4] One of the first cases of urushi was found in China. Lacquer covered wooden bowls were excavated in 1978 in Yuyao and Hemuda.[5] However, vessels that use both gold and lacquer developed around the Ming and Qing Dynasties (14th century BC) in China. [6]

Uruishi Vase
A single mature tree typically yields a ½ a cup of sap each year and is typically harvested every few years. The amount of sap was sometimes so scarce that the Japanese government would place restrictions on its harvest. The tree is a very close sibling to poison oak; the raw lacquer can cause extreme skin irritation. Even its vapors could cause potential harm for the craftsmen. To circumvent it, urushi artisans would sometimes expose themselves slowly to the raw lacquer creating immunity to it.[7]

The sap is typically applied to a wood (occasionally a metal) substrate in several layers. To make sure the wood does not warp, the craftsmen cure the wood. It can sometimes dry for up to seven years. After the wood is prepared, the first layer is applied to the substrate with a spatula and consists of pulverized clay, lacquer and water. After 24 hours, it is polished with a pumice stone and another ground layer is applied. Following this, the lacquer is brushed on in 20 layers.  Each layer is dried under specific conditions of temperature and humidity and polished with charcoal in between each layer. Depending on the artisan, additives would be added to the lacquer: ranging from drying oils, shellac or blood. When the final clear layer of lacquer is applied, it is filtered through rice papers to make sure there are no impurities. While the object is still wet from the lacquer, powdered gold and silver can be applied with a bamboo straw.

Urushi objects that are exposed to fluctuating changes in temperature and relative humidity exhibit micro cracking within each lacquered layer. In the Freer Sackler Gallery in Washington D.C., urushi objects are stored in a room with a constant temperature prevent cracking.[8] The lacquer’s rich tone fades with ultraviolet light as well. As light damage cracks the surface, this allows water to get into the urushi object. Like ormolu objects, in contrast to traditional housekeeping, the less the object is handled, the healthier the object remains.


Gilding is one of the favored ways to line with gold wooden sections of furniture and frames for paintings during the 19th century. The technique of gilding consists of applying gold leaf to a wooden substrate. The technology of gilding stretches as far back as three millennia beginning in the Middle Ages, starting in the Far East and later to Europe. The earliest decorative application of gold was in Egypt (c. 2400 BC).[9]

Gold leaf is created by a goldbeater, a worker that was once satirically described as having “joints [that were] pretty well knit” but whose “genius may be as low as can be conceived.”[10] To make golf leaf, gold in its molten state was combined with 1/80th of silver and copper to make the gold more malleable and poured into small ingots. As the job title goldbeater suggests, the workmen would beat the gold ingots repeatedly by passing it under steel rollers.

There are two different techniques of gilding: one is water gilding and the other is mordant or oil gilding. Water gilding was popularized in the 12th century and this is seen in the backgrounds of gold icons and medieval altar pieces.

In water gilding, a material called bole is first applied to the wood support. Bole contains clay (traditionally red or yellow), mixed with animal glue and water. After the bole is polished, the artisan brushes water, or, sometime alcohol, on top of the bole and the gold is applied using capillary action. When the surface has dried, it gets burnished with historically dog’s tooth.[11]

Mordant gilding (mordant literally means “to bite”) cements the gold leaf with linseed oil.  To make mordant gilding, the first layers of wood is treated with two to three coatings of oil mixed with white lead. It is then polished with shark skin and Dutch rushes, a plant also known as horsetail. When the oil is partially dried, the gold is applied with a squirrel’s tale brush or by hand.[12] Once the mordant is dried, excess gold is removed. Unlike water gilding, mordant gilding cannot be burnished as the adhesive is held too tightly to the ground. Mordant gilding is extremely durable and typically applied on panels and walls.

Workshop participant and blog author Fallon Murphy vacuums a gilded chair with a soft bristled brush.
Gilded objects are normally cleaned with a soft bristled brush and with a vacuum underneath the brush to catch the dirt. However, the vacuum does not touch the gilded surface as the gold is usually too fragile. Routine cleaning of the object is important as the corrosive buildup of dust is unhealthy for the object. Gilded surfaces are very hydroscopic and sudden changes in relative humidity and temperature is detrimental.[13]


Although all three techniques ormolu, urushi and gilding are mostly affected by similar changes in the environment (humidity, temperature change and light), but the way that an object deteriorates and responds to its environment is different. This is directly related to the way the object is made, its weaknesses, and its chemical makeup. The knowledge of how each object is created is essential for handling and monitoring the state of an object and the entire housekeeping plan.

Thoreau, in his book on perception, linked the act of seeing with knowledge, “Many an object is not seen, though it falls within the range of our visual ray, because it does not come within the range of our intellectual ray, i.e. we are not looking for it. So, in the largest sense, we find only the world we look for.” Learning about the way an object is created not only fosters an appreciation for the complexity of each object in front of me but also a language that might allow me understand and eventually help treat objects that are saturated in history.


[1]Chapman, Marin, “Techniques in Mercury Gilding in the 18th Century,” Ancient and Historic Metals Conservation and Scientific Research, ed Jerry Podany and Brian B. Considine. (The Getty Conservation Institute, 1994)

[2] Selwyn, Lyndsie, Metals and Corrosion A Handbook for the Conservation Professional, (Canada Conservation Institute: Canada, 2004)

[3] Kisluk-Grosheide, Danielle “The Art, Form and Function of Gilt Bronze in the French Interior,” (April 2008) http://www.metmuseum.org/toah/hd/gilt/hd_gilt.html

[4] Barchalia, Susanne, “Apprenticeship and Conservation,” Urushi: Proceedings of the Urushi Study Group, Edited by N.S. Brommelle and Perry Smith (The Getty Conservation Institute, 1988).

[5] Zhong, Zhou Bao, “Protection of Ancient Chinese Lacquerware,” Urushi: Proceedings of the Urushi Study Group, Edited by N.S. Brommelle and Perry Smith (The Getty Conservation Institute, 1988).

[6] Skalova, Alena, “Chinese Lacquer,” Urushi: Proceedings of the Urushi Study Group, Edited by N.S. Brommelle and Perry Smith (The Getty Conservation Institute, 1988).

[7] “Bone, Flesh, Skin: The Making of Japanese Lacquer,” Produced by The Asian Art Museum. https://www.youtube.com/watch?v=EkgCW-z-31w

[8] Chase, W.T. “Lacquer Examination and the Free Sackler Galleries: Some Case Histories,” Urushi: Proceedings of the Urushi Study Group, Edited by N.S. Brommelle and Perry Smith (The Getty Conservation Institute, 1988).

[9] Turner, Jane “Gilding I: Materials and techniques: Leaf Types and Application,” Grove Dictionary of Ar,t (Macmillan, 1996)

[10] R Campbell, The London Tradesmen (London: printed by T. Gardner, 1747).

[11]“Kress Technical Art History website: Gilding,” http://www.artcons.udel.edu/about/kress/historic-materials-technical-terms/gilding

[12] Fennimore, Donald L.,“Gilding Practices and Processes in Nineteenth Century American Furniture,”Gilded Wood: Conservation and History (Sound View Press: 1991).

[13] Robertson, Stanley, “The Routine Care and Maintenance of Gilded Wood Objects,” Gilded Wood: Conservation and History (Sound View Press: 1991).

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