Gilding
2 of the 6 encyclopedias on this shelf carry an entry for Gilding. Both are reproduced below, so you can see where they agree and where they differ.
The Encyclopedia of Founding (1892)
Important: Safety Warning
This page describes trade processes that use dangerously toxic materials such as cyanide solutions, mercury amalgams, or strong acids. These processes require training, equipment, and precautions far beyond what the text describes.
This information has been left in for historical purposes but should not be acted upon.
The three methods of gilding are: mechanical, chemical, and encaustic. Picture-frames, etc., are first oiled and then coated with whiting and glue, after which the gold size is applied to such parts as do not require burnishing; those which do are simply sized with the clear animal size. The gold-leaf is then applied with a brush. Electro-gilding is generally practised for metals. Water-gilding is simply applying a gold amalgam paste to the metal, and afterwards applying heat, which volatilizes the mercury, leaving the gold. The amalgam is made by placing grain or leaf gold 1 in a clean iron ladle, add mercury 8, and apply a gentle heat until the gold is dissolved, stir well with a clean iron rod, and run it on a clean slab. This, when cold, is the amalgam, ready for use. The cleaned metal to be gilded is first rubbed over with a solution of nitrate of mercury, and at once covered with a thin coat of the amalgam. Heat is then applied to volatize the mercury, and the gold adheres. Cheaper gilding may be made by increasing the quantity of mercury in the amalgam. Steel may be gilded by dipping the polished article into the ethereal solution of gold; on withdrawing, the ether evaporates, leaving the gold. A cloth dipped in the solution and wiped over the article answers the purpose. See STAINS FOR METALS; TINNING; ZINC COATING.
Aiton's Encyclopedia (1910)
an ancient art of applying a thin coating of gold to surfaces. This may be done by the use of gold leaf or by gold dust in solution. Traces of gilding have been found in the ruins of Egypt, Persia, Greece, and Rome. It was not uncommon to gild statues, ceilings, walls, and furniture. Metals are gilded by various methods, such as rubbing on dry, dipping in baths, applying in the form of an amalgam, paint, etc. The bookbinder uses gold leaf. Lettering and striping are done on leather and cloth by stamping gold leaf with hot brass type. Gilt edges preserve books against dust. They are made by first trimming the paper edges smooth and coating them with fish glue, the best made. The gold leaf is then applied with care to produce a smooth surface. The gold stripes of porcelain are applied with a camel's hair brush, and are burnt in to secure permanency. Among the buildings in which gilt has been used to secure massive effect, St. Peter's at Rome is an example. Gilt picture frames and cornices are used in modern houses, but are yielding to natural woods. The new Congressional Library at Washington is heavily gilded in a style of barbaric splendor, not in keeping with republican simplicity or correct taste. See Library Of Congress ; Painting
What Has Changed in the Last Century
The mercury amalgam process described by the Encyclopedia of Founding in 1892 "apply a gentle heat until the gold is dissolved" and then drive off the mercury as vapour is the reason for the safety warning above: fire-gilding poisoned generations of gilders, and it is now effectively extinct in industry, restricted by the 2013 Minamata Convention on Mercury and surviving only in a few licensed conservation workshops. Industrial gold plating today is done in electrolytic baths (long cyanide-based, increasingly in cyanide-free formulations) or by vacuum deposition and sputtering, and much decorative "gold" on watches, taps and tools is now titanium nitride or brass-coloured coating rather than gold at all. What has scarcely moved is the craft end: a gilder in 2024 still lays 23- or 24-carat leaf onto gesso, bole and animal size much as the 1892 account sets out, and bookbinders still stamp leaf with hot brass type. Aiton's 1910 dismissal of the Library of Congress gilding as "barbaric splendor, not in keeping with republican simplicity" has aged worst of all: the Thomas Jefferson Building was lavishly restored and regilded in the 1990s as a national treasure.
Written for this edition, 2026.