Authentic gold leaf is a decorative material made by hammering gold into very thin sheets varying in gold content and weight. Imitation gold leaf, also called composition gold leaf, Dutch metal, or Dutch gold, while made to imitate the appearance of gold, is made from a combination of copper, zinc, and brass. Both real and imitation gold leaf serve a common purpose- to coat a surface in order to give the appearance of solid gold.
Real Gold Leaf
How to Choose?
There are two factors to consider in choosing gold leaf, its value and weight.
Gold Content
Gold content expresses the purity of the leaf and ranges from 6 karat to 24 karat which is 100% gold. The degree to which the gold is mixed with silver or bronze will determine the karat value– silver will give a cooler tone and bronze a warmer tone. Gold content should be chosen in light of the project to be done, specifically whether the project is indoor or outdoor. All exterior projects should be gilded with gold leaf no less than 23.75 kt since gold is resistant to corrosion– the purer it is, the stronger it will resist rain, snow, sleet, and wind. Gold leaf of such value will maintain its integrity for 30+ years. Interior projects, since they are not subject to constant erosion, can be gilded with gold leaf of less than 23 kt. It is important to use a protective coating on leaf of low karat value to prevent oxidization and tarnish. Typically, interior gilding of architectural features is 22 karat.
Weight
Gold leaf is weighed in grams per 1,000 leaves. The heavier the gold leaf, the more resistant it is to corrosion. For this reason, a substantially heavy leaf is required for all exterior gilding projects– domes, statues, weathervanes, ornament. Typically, 18-23 grams per 1,000 leaves is recommended for exterior projects. As a studio, we will only use 21 or 23 grams. Interior gilding projects are considerably less vulnerable to erosion and it is therefore acceptable to use a lighter leaf in their completion.
In conclusion, exterior projects require gold leaf with a certain value and weight while interior projects allow for more flexibility.
Canning has used authentic gold leaf to execute a number of projects including St. Panteleimon Church, the War Memorial Opera House, St. Thomas More Church, the Cosmos Club, and Saint Cecilia Church pictured here from left to right.
Imitation Gold Leaf
Imitation leaf gives the appearance of solid gold despite the fact that it does not contain any gold at all. It is composed of some combination of copper, zinc, and brass and is much less expensive than gold leaf which is its primary drawing factor. Much like the low karat forms of authentic gold leaf, imitation gold is very sensitive to corrosion and is therefore not recommended for exterior projects. It is often used indoors and its desirability comes from its inexpensive nature and the fact that it is easier to handle.
Imitation gold leaf gilding in progress at a private residence can be seen here.
Which is Better?
If it can be afforded, it is usually more beneficial to use authentic gold leaf for both appearance and durability. The aesthetic of authentic gold leaf is much more consistent, rich, and brilliant than imitation leaf. Authentic leaf is also more practical since it will maintain its integrity for many years. Imitation leaf is subject to oxidation and tarnish and, even if sealed with a protective top coat, it will often not last more than a few years without acquiring a green, dull haze. Circumstances aside, using authentic gold leaf for a gilding project is usually worth the investment.
Although for the most part gold leaf is recommended, imitation leaf can be ideal for certain projects, especially interior gilding projects containing a lot of surface area to be covered. Ceilings, cornices, and other out of reach areas are most suitable for imitation gold.
