Making Gold leaf frames

Video from C&J frames showing Gold Leafing  

Traditional gold leaf frames are made using simple and ancient techniques. The ingredients are simple but that manufacture is a complicated skill.

Varieties of wood, chalk, rabbit skin glue, clay and gold are brought together to make frames good for palaces. These frames can last for an eternity given appropriate care and protection.

A frame is made from wood. It is sealed with a layer of rabbit skin glue to make it non absorbent. Decoration is either hand carved or built up with compo (composition ornament) - a pliable mix of rabbit skin glue, chalk and linseed oil.

Layers of white gesso are built up to give a smooth or shaped finish over the wood. Gesso is a thin plaster that is made from chalk suspended in rabbit skin glue. This gives it a strength while allowing it to be sanded smooth and shaped. The hardness is adjusted by the proportion of glue added, as well as the bloom (strength) of the collagen in the rabbit skin source. Traditionally it is applied by brush hot so it has a milton fluidity that changes quickly as it cools into a rubbery gell that dries hard. Modern gessos have been developed that can be sprayed on cold. This works for some frames but not others.

Care is taken not to have air bubbles, or flaws left in any layer. Any flaw will be amplified once gold leaf is applied.

Each layer of gesso is lightly sanded to ensure the correct shape and smoothness. Once completed bole is applied in a similar way to gesso. Bole is essentially the same as gesso but it is made with a colored clay rather than white chalk. It will have more, or harder, rabbit skin glue in it so that it adds strength and smoothness, rather than body, shape or texture. 

Bole will be made in a number of colors:

Red is ideal for a high carat gold leaf 24-18 kt. This gives the traditional warm color to gold leafing.

Yellow is used to keep gold leaf as bright as possible. It is forgiving as flaws in the gold leaf will show less.

Black, grey or blue are used with white gold leaf 13-12 ct. This silver looking leaf will gain a depth with dark and cool colored bole.

A few layers of bole will give a very smooth surface ready for gold leaf application.

If the gilder wants a bright gold shine on the frame he has no choice but to have a finely smooth surface and to use water gilding with real gold leaf. Where the surface does not need the delicate gossamer to bright gold effect metal, or dutch, leaf can be used. This is gold in color, much cheaper, easier to apply and good for many projects.

Water gilding is a challenging skill. Sheets of gold a few atoms thick are placed onto the frame which has been wetted. The wetting agent varies but it can be simply water as the bond between the gold and the glue is atomic rather than mediated by any. Sometimes rabbit skin or brandy is added to the water.

The water enables the gold to attach itself to the bole. Cotten wool is used to tamp the leaf down pushing out spare water. As it dries the gold is drawn onto the surface of the clay. 

Once the gold has dried, and before the clay is too hard it can be burnished with an agate tool. This pushes the gold down onto the surface of the bole to enable the smooth surface of the bole to show through the gold. The shiny surface of burnished gold is more about the quality of the sootiness of the bole than the flattening of the gold by the agate tool