"Baggot Leaf Gilding Glossary"
Bole: Clay mixed with rabbit skin glue for application to the surface of an object being prepared for water-gilded. Usually the clay is applied to a gesso surface. It is the clay surface that receives the gold leaf. The clay and rabbit skin glue content dictate the reflective quality of the gold finish. Clay is finer than gesso and when burnished with a tool of hounds tooth, agate or hematite stone its surface becomes more dense and thereby more reflective.
Burnishing: Rubbing a surface with stone or a hard implement condensing the surface and creating a reflective surface. In gilding, rubbing the clay and/gold surface with a hound's tooth, agate or hematite stone. Burnishing a water-gilt surface produces the most reflective gold surface possible. Burnishing is often employed selectively to enhance decoration by creating depth or accenting architectural aspects of the object. It is the properties of the rabbit skin glue that allow for burnishing. Other glues also have properties that enable burnishing like fish glue and gelatin.
Bronze Powder: Particles of bronze used as a pigment and mixed with a medium to produce a gold-colored finish. These finishes tarnish due to the copper content of bronze powders. They reflect light differently than leaf, the finishes they produce are thereby grainy in comparison. There are binders that allow some degree of burnishing of very finely ground bronze powders, producing a far less grainy and more reflective finish than regular bronze powders would produce. Bronze powders are toxic, especially when air born.
Clay Brush: A soft flat wash brush, with a bevelled edge or soft , thin, long bristled brush carefully chosen to aid the gilder in the best possible clay layer applications. Clean with water and mild soap. Paint stirrers can be used to liquify clay in a separate container before brushing.
Cochineal: Made from interesting bugs harvested in Peru. It is used to create a transparent pigment making it attractive to gilders as a pigmentation material for finishes on leafed surfaces. It produces a brilliant scarlet.
Custom Palette: The leather made from the skin and bones of rabbits. A glue which will set to an extremely strong jelly. The leather is "conditioned" by rubbing it with the "roughed" tissue pages from an empty gold leaf book. This powder coating prevents the leaf from holding too tightly to the leather.
Delamination: When adhesives breakdown and surfaces that were once joined separate. The separation is delamination. The gesso of a water-gilded surface can delaminate from the wood surface of the object due to the shrinkage of the wood and/or adhesive failure. Layers of gesso or layers of gesso and clay can separate if the glue content of the different layers is not correct. Impurities between layers can cause trouble as well.
Fish Eye Glue: Made from the eyes and yaws of fish, this glue is highly hygroscopic.
Gesso Sottile: A traditional gesso commonly used for the raised gilding of manuscript illumination. Its properties are flexibility and strength. It can support the movement of turning pages without cracking or delaminating. Its binder is usually fish glue and old recipes for Gesso Sottile include white lead rendering them poisonous. Acrylic gesso sottile is available today and is considered an acceptable replacement.
Gilder's Garlic: Garlic juice used as a mordant for gilding. A technique usually found on paper but it is also known to be used on furniture and decoration.
Gilder's Liquor: A mix of water and alcohol used in water-gilding sometimes with the
addition of rabbit skin glue. It is mopped on to the clay surface to activate the glue in the clay before gold leaf is applied. In effect the gold is laid on this liquid surface and then adheres to the clay surface as the water is absorbed.
Gilder's Malt: A concentrated brew of malt used as a mordant for gilding. It is usually thick in consistency and can be thinned with water. A mordant usually found in gilding on paper but it is known to have been used on furniture and decoration.
Gilding: To overlay with or as if with a thin coating of gold.See also: R. Mayer Append. #1
Gold Leaf: Gold beaten to the point of being transparent. A special thickness of leaf is employed by glass gilders for this reason. Traditionally, gold was beaten by hand but get thickness measurement. Today it is beaten by machine producing a thinner leaf. It is cut into approx. 3"X 3" squares and sold in books of 25 leaves. Leaf can not be touched by hand or it will disintegrate. The leaf is transferred to an object with a brush called a Gilders Tip. The nature of the finish the gold leaf produces depends entirely on the surface upon which it is places. Finishes range from matte oil gilding surfaces to brilliant, burnished clay surfaces with water-gilding. The advantages of a gold leaf finish as opposed to other gold colored finished are: Its reflective quality (The beaten leaf has more reflective quality than anything produced with pigment), its durability (properly gild surfaces can last for centuries) and its stability (it does not tarnish).
Gold Leaf Criteria for Evaluation:
Karat - 24 karat gold is pure gold with no other metal added. 12 karat gold is 50% gold and 50% other metal. The karat weight of gold leaf ranges from 12 karat white gold to 24 karat, 22 & 23 karat being the most popular for leafing.
Color - The metals mixed with gold in its making change the color of the gold produced. There can be different colors of gold within the same karat. 23kt gold can be a Red Gold, a Rosenoble or a Duketen. Lemon gold was generally a term for gold that was not red. Today it can indicate an 18 karat gold instead of 24 karat gold.
Imperfections - there are often imperfections in the structure of the leaf. They are small holes, areas where the leaf may have been beaten too thin or the leaf became damaged in handling. When gilding on glass the light passing through the imperfections of the leaf on the glass accentuating the imperfections of the leaf. Slight imperfections, meaning small pin holes, are hardly noticeable when gilding on surfaces other than glass. The terms used for judging this quality are "glass grade" meaning perfect to "surface" meaning slight imperfections.
Weight - Given as grams per 1000 leaves ranging approx. from 11.3 to 29 grams. Each manufacturer would have its own in house nomenclature for describing weight like X, XX, XXX or Double and Regular. There was an issue of how the leaf was beaten, hand or machine beaten. The gold beating industry has found hand beating financially unfeasible and has converted to automation. The automated process of beating gold allows for better control of leaf weight produced. This weight varies significantly from manufacturer to manufacturer.
Gum Ammoniac: It is a plant resin. Dissolved in alcohol it is used as a mordant for gilding. This is a technique found on paper and parchment.
Isinglass Glue: A binder made from fish air bladders. Appreciated by manuscript illuminators for its strength and flexibility as a binder.
Knife: Used to cut gold leaf. It should be cleaned with alcohol or acetone to remove the machine oil. Care for it and sharpen it as you would any good blade. Very fine grit paper or emery cloth should provide a sufficient sharpening abrasive. Its purpose is to clearly break the leaf not cut it. Though a modified cutting motion is used.
Metal Leaf: Also known as Dutch Metal and Composition Leaf. Metal leaf is an alloy of gold-colored base metals (Copper, Tin and Zinc). It is produced in leaves that are thicker and larger than gold leaf. They can be manipulated by hand. Metal leaf will tarnish and will eventually disintegrate completely.
Mica Powder: Mica is a mineral ground and treated to create a gold colored pigment. It can be mixed with a medium and applied to a surface. It is usually employed in exactly the same manner as bronze powders were. It is an excellent substitute for bronze powders because of its stability. It will not tarnish or chemically react with its medium. It is non-toxic unlike bronze powders.
Mop: Gilder's Mop - The name of the brush used to lay the gilding liquor on the clay surface just prior to laying the gold. This brush came by its nickname because of its capacity to hold a large amount of liquid. The objective is to mop on a lot of liquid not to mop it up.
Oil Gilding: The application of gold or metal leaf to a surface employing an adhesive. This resin traditionally is an oil based varnish known as size. Water based substitutes are also available. Most surfaces to be oil gilt need to be sealed to ensure an evenly distributed layers of adhesive and an even drying time.
Ox Gall: It was employed to aid in the mixing of oil containing pigments and water when creating paints.
Pad: Custom Palette/Gilder's Pad - A board covered with padding and leather. It should be small and light enough to be held in one hand for long periods of time. The pad is used for cutting the 3" X 3" gold leaves into smaller more manageable pieces with a gilder's knife. There can be a parchment or wind shield attached to this board to protect the gold on the pad from being blown away by passing breezes or co-workers. The leather ... made from the skin and bones of rabbits. A glue which will set to an extremely strong jelly.
Parcel Gilding: Selective gilding when only specific areas or decoration are gilded.
Rabbit Skin Glue: The binder used in traditional water-gilding.
Rub-On Gold Finishes: Also known as 'Rub and Buff', 'Treasure Gold Wax', 'Gilt Sticks' or 'Gilt Cream'. These are gold colored pigments mixed into a wax medium. These finishes will tarnish due to the properties inherent in the copper content of bronze powders. Many of these can be made in house using clear waxes and mica powders.
Patination: The effects of time on an object and the finish it imparts.
Tip: Gilder's Tip - A small card, like an index card, that has a row of squirrel hairs attached. The tip is used to pick up and apply gold and metal leaf. A small amount of oil is applied to the tip from the skin or hair. The leaf is attached to the oil in the tip allowing one to pick up the leaf. The attraction of the leaf to water or the leaf to size is stronger than the attraction of the leaf to oil allowing one to lay the leaf on the object.
Toning: The application of pigment and/or other materials to a gilded surface. Toning can also include the removal of gold from a gilded surface. It literally means toning down the brilliance of a gilded surface. Toning is usually employed to replicate age. Toning is also employed as a final step in the restoration of gilding to replicate the original patination of the object.
Water-Gilding: The application of gold leaf to a wood substructure that has been prepared with layers of gesso and clay. The binder in this technique is traditionally rabbit skin glue. This technique offers the most brilliance possible in a gold finish. It is the most manipulable gold finish available, having the widest range of possibilities between matte & brilliant. A burnish water-gilt surface is the most reflective finish possible.
Whiting: Marble Dust, Powdered Gypsum. In water-gilding whiting is mixed with specific amounts of rabbit skin glue to make gesso.
Sandpaper: Is used to dry and brush strokes which may occur in the last layer.
Steel Wool: As well as hair cloth are traditionally used to polish and darken the final clay layer to a high shine. Dust away steel fillings before gilding.