S E C T I O N IV.
Of burntjh gilding; with the prepara-tion of the proper fzes^ &c.
TH E gilding with burnifht gold is fel-dom pradtifed, but upoh wood j and at prefent moftly in the cafe of carved work, or where carved work is mixed with plain. The
chief difference in the manner betwixt this and oil gilding lies in the preparing the work to receive the gold j and in the fubftituting a fize made of parchment, or the cuttings of glover’s leather in the place of the fat oil, as a cement: the preparation of which fize fhould, therefore, be previoufly known j and may be as follows.
“ Take a pound of cuttings of parchment, ** or of the leather ufed by glovers; and, ** having added to them fix quarts of water, “ boil them till the quantity of fluid be re** duced to two quarts: or till, on the tak** ing out a little, it will appear like1 a jelly on “ growing cold. Strain it through flannel while hot j and it will be then fit for ufe.” This fize is employed in burnifh gilding, not only in forming the gold fize, or cement for binding the gold to the ground; but alfb in priming, or previoufly preparing the work: but before I proceed to lhew the manner of ufing it fo, it is neceflary to give the compofi- tions for the proper cement or gilding fize employed in this kind of gilding. There are a multiplicity of recipes for this compofition, which are approved of by different perfons: but as in general they vary not effentially from each other, 1 will only give two, which I believe to be each the belt in their kinds. •
“ Take any quantity of bole armoniac, and add fome water to it, that it may foak till it tc grow foft; levigate it then on the ftone, “ but not with more water than will prevent
“ its being of a ftiff confidence; and add to it “ a little purified fuet or tallow fcraped; and “ grind them together. When this is wanted for “ ufe, dilute it to the confidence of cream, by “ parchment or glovers fize, mixt with double “ its quantity of water, and made warm. Some “ melt the fuet or tallow, and mix it previoufly ** with five or fix times its weight erf chalk be“ fore it is put to the bole, to facilitate their “ commixture; to which in this wet date they ** are otherwife fomewhat repugnant. It is “ alfo fbmetimes pradtifed to put fope-fuds to “ the bole; which will contribute to its unit“ ing.with the tallow.”
This is the fimpled compofition, and equally good with the following, or any other; but for the indulgence of the variety of opinions, which reigns in all thefe kinds of matters, I will infert another.
“ Take of bole in fine powder one pound, “ and of black lead two ounces. Mix them “ well by grinding; and then add of olive “ oil two ounces, and of bees-wax one ounce, “ melted together; and repeat the grinding “ till the whole be thoroughly incorporated. “ When this mixture is to be ufed, dilute it “ with the parchment or glovers fize, as was “ directed in the former recipe: but, in the “ mean time, both this and the foregoing “ fhould be kept immerfed in water, which “ will preferve them good.”
To prepare the wood for bumifh gilding, it fhould firft: be well rubbed with the fifb-ikin; and then with the Dutch rufhes: but this can only be pradtifed in the larger and • plainer parts of the work, otherwife it may damage the carving, or render it lefs (harp by wearing off the points. It muft then be primed with the glovers fize, mixed with as much whiting as will give it a tolerable body of colour : which mixture muft be made by melting the fize, and ftrewing the whiting in a powdered ftate gradually into it j ftirring them well together, that they may be thoroughly incorporated. Of this priming feven or eight coats fhould be given, time being allowed for the drying of each before the other be put on; and care fhould be taken, in doing this, to work the priming well, with the brufh, into all the cavities or hollows there may be in the carved work. After the laft coat is laid on, and before it be quite dry, a brufti pencil dipt in water fhould be pafled over the whole to finooth it and take away any lumps or inequalities that may have been formed: and when it is dry the parts which admit of it fhould be again rufhed over till they be perfectly even. The work fhould then be repaired by freeing all the cavities and hollow parts from the priming,’ which may choak them, or injure the relief of the carving: after which a water polifh fhould be given to the parts defigned to be burnifhed, by rubbing them gently with a fine linnen rag moiftened with water.
. The work being thus prepared, when it i? to be gilt, dilute the compofition of bole, with warm fize mixt with two thirds of water; and with a brufh fpread it over the whole of the work, and then fuffer it to dry; and go over it agbin with the mixture, in the fame manner, at lead once more. After the lad coat, rub it in the parts to be burnifhed, with a foft cloth, till it be perfectly even. Some add a little vermilion to the gilding fize, and, others colour the work, if carved, before it be laid on, with yellow and the glovers fize; to which a little vermilion, or red lead, ftiould be added. This lad method is to give the appearance of gilding to the deeper and obfeure parts of the carving, where the gold cannot, or is not thought neceflary, to be put: but this practice is at prefent much difufed; and indead of it fuch parts of the work are coloured after the gilding •, which taeatment is called matting.
Having the work properly prepared, and let in a pofition almod perpendicular, but declining a little from you, and having the gilding fize, and all the neceflary indru- ments above defcribed ready, as alfo a baton of clean water, wet the uppermod part of the work, by means of a large camel’s hair pencil dipped in the water; and then lay on the gold upon the part lb wet, in the manner above diredted for the gilding in oil,, till it be completely covered, or become too dry to take the gold: and then proceed to wet the next part of the work, or the fame over again if neceflary, and gild it as the firft; repeating the fame method till the whole be finiffied. Some wet the work with brandy, or fpirit of wine, inftead of water; but I do not conceive any advantage can arife from it, that may not be equally obtained by a judicious uie of water; and this manner is much more troublefome and difficult, as well as ex- penfive, for only a fmall part mull: be wet at one time, and the gold laid inftandy upon it; or the brandy or fpirits will fly off, and leave the ground too dry to take the gold.
The work being thus gone over with the gilding, mull: be then examined; and fucfa parts as require it repaired, by wetting them with die camels hair pencil, and covering them with the gold; but as little as poffibe of the perfect part of the gilding fhould be wet, as the gold is very apt to turn black in this ftate. When the repaired part alfb is dry, the work may be matted if it require it: that is, the hollow parts mu ft be covered with a colour the neareft in appearance to gold. For this purpofe fome recommend red lead, with a little vermilion ground up with the white of an egg: but I think yellow oker or Dutch pink with red lead, would better anfwer the end: or the terra dc Siena very llighdy burnt or mixed with a little red lead would have a much better efleft; and be more durable than any other mixture fo near the colour of gold in fhade. Ifinglafs fize will likewise equally well fupply the place, of the whites of eggs in the compofition for matting. -
The work “being thus»gilt, it muft remain about twenty-four hours; and then the parts of it that are defigned to be burnifhed, muft be polifhed with the dog’s tooth, or with the burnifhers of agate or dint made for this pur- pofe: but it fhould be previoufly tried, whether it be of the proper temper as to the dry- nefsj for though twenty-four hours be the moft general *fpace of time, in which it becomes fit, yet the difference of feafon, or the degree of wet given ta the work, makes the drying irregular, with regard to any fixt period. The way of diftinguifhing the fitneft of the work to take the burnifh, is to try two or three particular parts at a diftance from each other; which, if they take the polifh in a kindly manner, the whole may be concluded fit: but if the gold peel off, or be difor- dered by the rubbing, the work muft be deemed not yet dry enough: and if the gold abide well the rubbing, and yet receives the pblifh flowly, it is a proof of its being too dry: which fhould be always prevented by watching the proper time; as the work, when too dry, both requires much more labour to burnifh it, and fails at laft of taking fo fine a polifh.