GLOSSARY

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G

galvanic corrosion

A type of corrosion which is caused by an electric current flowing between two dissimilar alloys or metals which come into contact with each other. Under these circumstances, the more reactive metal or alloy corrodes while the less reactive metal is protected. For example, if iron and copper were in direct physical contact in the presence of moisture and oxygen, the iron would selectively corrode while simultaneously protecting the copper.

gauffered, goffered

This term refers to book edges, almost invariably gilt, which have been decorated using hot finishing tools that indent small patterns into the paper. Also spelt goffered and sometimes called chased edging. See also Gilded, gilt.

gelatine

A complex protein extracted from animal cartilage and bones by boiling in water. Soluble in water, it also sets to a jelly. Gelatine is used in foods and photography, and as an adhesive and textile size.

genotoxic

Poisonous to the genes.

gilded, gilt

Covered or decorated with gold leaf. Gilding is used in paintings and as a decoration of painting frames, but it is also seen in book decoration. Although the term is often used to refer to the decoration of both leather covers and edges of a book, it is more accurately applied only to book edging, and the term gold tooling is used for book covers. See also Gauffered, goffered; Gold tooling.

glair

An adhesive mixture of egg white-albumen-and vinegar, which is applied in a thin coating to a book cover before tooling in gold leaf. It causes the gold to adhere permanently to the book when a heated tool or stamp is impressed upon it. See also Albumen, Gold tooling.

glazing

Glass or Perspex used in framing.

glossy paper

Paper with a smooth, glossy surface. This can either be produced using coatings or by 'polishing' or 'calendering' the paper during manufacture. See Coated paper.

gold toning/gold toner

A process for converting part of the silver of a black and white photographic print to gold, which produces a blue colour. If the print is first toned to a sepia colour and then gold toned, the result is a brilliant red. When gold is added to a sulphur toning bath, the colour of the sepia image is enhanced.

gold tooling

Book decoration where a pattern, letters or lines are impressed into the leather spine and covers of a book, using gold leaf and a heated tool or stamp. See also Blind tooling; Glair.

grit

See Particulate matter.

ground

The substance applied to a surface before painting is begun. Before the 20th century, a mixture of gypsum, chalk or marble with a glue medium was used as a ground. The ground is often, but not always, an intermediate layer between the paint and its support.

growth regulator

A synthetic substance which produces the effect of a naturally occurring hormone in inhibiting growth; used in conservation work as a non-toxic means of insect control.