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How to Write a Specification For Gilding & Gold Leafing Application

Gilding is a truly ancient process, believed to have been first developed in Turkey over 8,000 years ago. The ancient Egyptians used it embellish the sarcophagi of pharaohs, the Phoenicians used it to plate less expensive metals to sell them for more at market, and more recently Europeans have used gilding to cover surfaces ranging from ceilings, wood frames, to dinnerware. While many of the processes to apply gold leaf are rooted in similar principles, the process has evolved greatly with time—which has made the process safe and ensures that the finish lasts longer. When it comes to writing a specification, it is important to do a pre-project investigation to understand not only the scale of the needed gilding restoration, but also understand what are the underlying issues causing the gold leaf finish to fail. Is the project indoors or outdoors? What is the base material to which the gold leaf was applied? How was the gold bonded to the surface? Is that the most effective method? Developing a baseline understanding of these key questions will ensure your conversations with prospective restoration professionals remains grounded. Additionally, we encourage prospective clients to do the following four things prior to starting any gold leaf project or specification:

1. Understand the Gilding Process

Application methods change based on the material the gold leaf is being applied. These are a few of the most common types of gilding applications:

Mechanical Gilding

  • Overlaying: this is the simplest form of gilding and is most likely the original form used in ancient times—references to this type are made in both Greek mythology and the Bible. Heated gold is hammered into thin sheets and then applied once cooled to the intended surface; note that the layer of gold associated with this process is significantly thicker than golf leaf which, was not invented until the Middle Ages. A layer of adhesive is applied to prepare the surface—most commonly it is a simple adhesive made from vegetation and/or animal bones. In ancient times, bitumen (asphalt) was commonly used as the adhesive.
  • Water gilding: enables the gold finish to be mirror-like and polished in appearance. This process uses ground gypsum/chalk mixed with glue as a base coat. The surface is dampened and then buffed again with water.
  • Oil-gilding: similar to water gilding, however, the surface is buffed with an oil to finish—typically linseed oil.

Chemical Gilding

  • Cold Gilding and wet gilding are process used to apply gold to metal surfaces; the former to sterling silver (vermeil finish) and the latter to more generalized metals.

2. Determine the Scope

How large is the project at hand? Are there confounding variables, like active water damage that if unresolved could damage the restored surface? It is important to know as many variables as possible, prior to consulting experts. By thoroughly reviewing the scope of the proposed restoration, you will be able to get a feel for not only what you are trying to achieve with the restoration, but also the kinds of experts are needed to help you accomplish it.

Prior to starting on the project, a conservator would typically run an adhesion test. The goal of this test is to determine areas of failure and their cause(s).

Gold Leaf damage

3. Establish The Key Requirements

The restoration needs to be done correctly, regardless of scale. It is important to define what qualifications you want a conservation expert to have. Any expert you consult with should meet the AIC code of ethics—a guideline for professional conduct within the conservation community.

There are additional standards that are material-specific but are crucial for long-term success. The nuances of applying different materials (interior/exterior gold leaf, Dutch metal, and copper leaf) can be vast, so it is paramount that the company you choose to work with has experience with both the medium you are applying and the surface it is being applied to. Remember, indoor and outdoor gold leaf applications require different standards, so make sure they have the right body of experience.

It is very important to obtain a second opinion. By comparing specifications from multiple conservation teams, you can compare their assessed scope, material selections, finishing techniques, and any pre-project scientific test. These pieces of information will give you a perspective of the kinds of skills needed in a conservator.

Gold Leaf damage

4. Obtain References

Obtaining references is an important step prior to selecting a conservation expert. Reviewing with past clients the not only the quality of the outcome, but also the restoration process can give you important perspective. Ensure that you consult past clients with project similar to yours—in this case, it would be important to review with clients who had gold leaf restored in a project commensurate in scale and situation to yours.

Additionally, try to obtain references from professional trade partners a perspective conservator has worked with—architects, contractors, and subcontractors. They should be able to provide sufficient references.

Canning C

October 30, 2019

Featured Projects

Boston State Street Building

75 State Street

John Canning & Co. craftsmen completed the gold leaf work over the course of two seasons for this Boston building.

Cosmos Club

John Canning & Co. scheduled all trades and performed specialty contracting to conserve and restore fine-art murals, ornamental plaster, gilding, decorative finishes and the parquet floor of the ornately decorated Cosmos Club ballroom in Washington, DC.

Rockefeller Center Gilding Feature

Prometheus Fountain Gold Leaf Restoration

We restored the Prometheus Statue, a National Historic Landmark located in Rockefeller Center using gold leaf gilding.

yale divinity school

Divinity School,Yale University

John Canning & Co. was the contracted to perform the gilding of the dome for the Yale University’s Sterling Divinity School Quadrangle Chapel Steeple.

John Canning & Co.'s Art of Exterior Gilding and Domes Resource
John Canning & Co. Resources

As a conservation studio and restoration contractor, our team of highly skilled craftsmen, artisans, and conservators are experienced in the use of traditional methods and materials. We understand the importance in sharing our expertise and knowledge in our field.

Check Out Our Guide For The Art of Exterior Gilding