A Little ‘Alchemy’

Cabinet fittings were an expensive commodity in the seventeenth-century: Iron handles were individually fashioned by blacksmiths, whitesmiths and specialist hardware makers. The last quarter of the seventeenth-century saw the introduction of expensive sand-cast brass fittings, meaning multiples of practically identical handles, escutcheons and hinges etc., could be produced at the same time. All the same, the time saved by casting was offset by the fiddly and laborious procedure of filing the rough castings (the evidence of which is often still apparent on period originals). The final stages of the process were buffing the brasses with successively finer abrasive compounds and, in the case of some examples, gilding them.

Gilding was yet another accrued expense in the progression that was performed by a group of workers with very short life expectancy. Fire-gilding – to give it its proper title and not to confuse it with oil- or water-gilding – entailed a potentially lethal process whereby gold was dissolved in highly toxic mercury. In Polygraphice [i], William Salmon described the process of gilding on brass and silver with “Gold Water”:

Take Quick-ſilver [mercury] two ounces, put it on the fire in a Crucible, and when it begins to ſmoak, put into it an Angel of fine Gold [seventeenth-century gold coin]; then take it off immediately, for the Gold will be preſently diſſolved : then if it be too thin, ſtrain a part of the Quick-ſilver from it, through a piece of Fuſtian : this done, rub the Gold and Quick-ſilver upon Braſs or Silver, and it will cleave unto it, then put the ſaid Braſs or Silver upon quick coals till it begin to ſmoak, then take it from the fire, and ſcratch it with a hair bruſh ; this do ſo long till all the Mercury is rubbed as clean off as may be, and the Gold appear of a faint yellow: which color heighten with Sal Armoniack, Bole and Verdigriſe ground together and tempered with water.

An alternative to gilding brasses, and one that, when well executed, is virtually indistinguishable from the genuine article, is gold-lacquering. No actual gold is used, rather, successive coats of dilute translucent reddish-yellow lacquer are applied to clean, polished brass. The result is not as hardwearing as fire-gilding, but is a very passable substitute and was highly regarded during the eighteenth-century.

… a proportionable number of recipes have been deviſed and introduced into practice, eſpecially for the lacquering braſs work to imitate gilding, which is a conſiderable object in this kind of art, and has been improved to the greateſt degree of perfection.

The following are excellent compoſitions for braſs work which is to reſemble gilding:

“Take of turmeric ground, as it may be had at the dry-ſalters, one ounce, and of ſaffron and Spaniſh annatto, each two drams. Put them into a proper bottle, with a pint of highly rectified ſpirit of wine [ethyl alcohol], and place them in a moderate heat, if convenient, often ſhaking them for ſeveral days. A very ſtrong yellow tincture will then be obtained, which muſt be ſtrained off from the dregs through a coarſe linen cloth ; and then, being put back into the bottle, three ounces of good ſeed-lac, powdered groſsly, muſt be added, and the mixture placed, again in a moderate heat, and ſhaken, till the ſeed-lac be diſſolved ; or at leaſt ſuch part of it that may.

First, let the pieces of work to be lacquered be made thoroughly clean; which, if they be new founded, muſt be done by means of aqua fortis [nitric acid]. Being ready, they muſt be heated by a small charcoal fire, in a proper veſſel, or any way that may be moſt convenient ; the degree muſt not be greater than will admit of their being taken hold of without burning the hand. The lacquer muſt then be laid on by a proper bruſh in the manner of other varniſhes ; and the pieces immediately ſet again in the ſame warm ſituation. After the lacquer is thoroughly dry and firm, the ſame operation muſt be renewed again for four or five times, or till the work appear of the colour and brightneſs intended. For very fine work, ſome uſe a leſſ proportion of ſeed-lac which occaſions the lacquer to lie more even on the metal ; but, in this caſe, a greater number of coats are required, which multiplies the proportion of labour, though where the price of the work will allow for ſuch additional trouble, it will be the more perfect for it. [ii]

Polished (left) and gold-lacquered Dutch drop handles.


[i] William Salmon, Polygraphice, or, The Arts of Drawing, Engraving, Etching, Limning, Painting, Vernishing, Japaning, Gilding, &c., eighth edition,A. and J. Churchill, and John Nicholson, London, 1701, p. 216.

[ii] The Artist’s assistant; or School of Science; Forming a Practical Introduction to the Polite Arts, Swinney & Hawkins, Birmingham, 1801, pp. 210-15.

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About Jack Plane

Formerly from the UK, Jack is a retired antiques dealer and self-taught woodworker, now living in Australia.
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5 Responses to A Little ‘Alchemy’

  1. Devin says:

    Did you actually use turmeric- and saffron-tinted alcohol to dissolve your shellac?!? I once used turmeric to dye some fabric, but it faded in sunlight in a matter of days. Does this finish seem to retain its color on real antiques? Perhaps the absence of air prevents the color from degrading…

    Nice post! Scary, but interesting. It makes me wonder what future craftsmen will have to say about today’s “safe” practices.

    Like

    • Jack Plane says:

      I have used turmeric and dragon’s blood in the past and it works very well. On this occasion I did use turmeric and dragon’s blood for accuracy’s sake, but to be honest, the same results can be achieved more conveniently with spirit aniline dyes.

      Mercury gilders, looking glass silverers, lead pigment grinders, hatters etc. were fully aware of the toxins they employed and their health effects. The difference nowadays is that many industrial processes have become extinct because of our litigious culture and, in some instances, overly-protective legislation. I believe, if anything, we’re too well protected now and have little choice in the matter.

      Like

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