Gesso - is a mixture of size and whiting, which is heated and six or more coats are painted onto the wooden frame. It is sanded to a smooth finish.
Bole - a mix of coloured clay and rabbit skin glue. This is also heated up and painted on top of the gesso. Yellow is the main colour however, depending upon when and where the mirror originates, the colours can vary. For example, in France they used a red/orange bole, this is usually found under the water gilded burnished highlights. In England we used pink, followed by black.
Composition - (compo) there are many compo recipes each with the same three basic ingredients are glue, rosin and whiting, but other ingredients are added to improve on this. Compo when warm can be pushed into moulds or carved when cold. It sets hard over a few days but over the years it does dry out and small cracks appear.
Oil Gilding - an oil size (or mordent) that is painted onto a prepared surface and after becoming tacky the gold is applied. This form of gilding cannot be burnished. Oil gilding can be used for both internal and external surfaces.
Water Gilding - (See photo above) a water and glue solution that is brushed onto the smoothed bole surface, the gold is laid on immediately with a gilder's tip. By using this technique, the gold then can then be burnished.
Gold Leaf - the gold is virtually pure; I use 23 and three quarter and 23 and a half carat.
Gilder's Tip - a wide flat brush made traditionally from badger hair; it is used for picking up the gold leaf.
Burnishing - rubbing the surface of the gold with an agate.
