SECTION V.
Of Japaners gilding.
THE Japaners gilding is performed by means of gold powder, or imitations of it, cemented to the ground by a kind of gold fize much of the nature of drying oil: for the making which, there are various re-cipes followed by different perfons. I fhall, however, only give one of the more compound, that is much approved; and another very
fimple, but which, neverthelefs, is equally good for the purpofe with the mod elaborate. The more compound gold fize may be thus made.
“ Take of gum animi and afphaltum each
“ one ounce, of red lead, litharge of gold, and
“ umbre, each one ounce and a half. Re-
“ duce the grofi'er ingredients to a fine pow-
“ der; and having mixed them, put them,
“ together with a pound of linfeed oil, • into
“ a proper veflel, and boil them gently; con-
“ flantly flirring them, with a flick or to-
“ bacco-pipe, till the whole appear to be.in-
“ corporated. Continue the boiling, fre-
“ quently flirring them, till on taking out a
“ fmall quantity, it appear thick like tar, as
“ it grows cold. Strain the mixture then
through flannel; and keep it carefully flopt
up in a bottle, having a wide mouth, for
“ ufe. But when k is wanted, if mud be ground with as much vermilion, as will give it an opake body, and at the fame “ time diluted wkh oil of turpentine, fo as to> rt render it of a confidence proper for work** ing freely with the pencil."
Tne afphaltuna does not, I conceive, contribute to the intention of this kind of fize: and the litharge of gold, and red lead, are both the fame thing, with relpe<ft to this purpole, under different names: and neither they nor the amhre nocdfary, but clogging ingre-* clients to the compofition.
This gold fixer may therefore be equally well, or perhaps better prepared, in the following manner.
*c Take of linfeed oil one pound, and of ** gum animi four ounces. Set the oil to_ “ boU in a proper veflel; and then add the “ gum animi gradually in ponder; dirrirrg each quantity about in the oil, till it appear “ to be diflolved; and then putting in ano- ** ther, till the whole be commixt with the ** oik Let yhe mixture continue to bod, till, “ on taking a fmall quantity out, it appear of “ a thicker confidence than tar: and then “ drain the whole through a coarfe doth, and “ keep it da: ufe: but it mud, when ufed, be <c mixed with vermilion and oil of turpentine,
“ in tho manner directed for the foregoing.” This gold fixe may be ufed on metals, wood, or any other ground whatever: but before I enter on the particular manner of gild- ing with it, the preparation of the true, and counterfeit, gold powders are neceflary to be lhewn. '
The true gold powder may be well and ealily made by the following method.
“ Take any quantity of leaf gold; and grind “ it with virgin hony, on a ftone, till the “ texture of the leaves be perfectly broken,
#c and their parts divided to the minuteft de“ gree. Then take the mixture of gold and | “ hony from off the ftone; and put it into a
.4 “ China or other fuch bafon, with water;
j “ and ftir it well about, that the hony may ,
j “ be melted; and the gold by that means
j “ freed from it. Let the bafon afterwards
j. u ftand at reft, till the gold be fubfided; and
1 «* when it is fo, pour off the water from it;
j “ and add frelh quantities till the hony be in; “ tirely waftied away; after which die gold
cc may be put on paper, and dried for ufe.” The German gold powder, which is the kind moft generally ufed, and, where it is well fecured with varnilh, will equally anfwer the end in this kind of gilding with the genuine, may be prepared from the fort of leaf gold, called the Dutch gold, exadtly in the fame manner as the true.
The aurum Mofaicum, which is tin coloured, and rendered of a flaky or pulverine tex. ture, by a chemical procefs, lb as greatly to refemble gold powder, may be like wife ufed in this kind of gilding; and prepared in the fallowing manner, .
“ Take of tin one pound, Of flowers bf l£ fulphur feven ounces, of lal ammoriiacum ££ and purified quickfilver each half a pound; t£ Melt the tin j and add the quickfilver to it ££ in that ftate: and when the mixture is bei 4£ come cold, powder it, and grind it with the fal ammoniacum and fulphur, till the “ whole be thoroughly commixt. Calcine 4£ them then irt.a mattrafs j and the other in- ££ gradients fubliming, the tin will be convert* _ ££ ed into the aurum MofaicUrh j and will be^ *£ found in the bottom of the glafs like a maß “ of bright flaky gold powder: but if any *£ black or difcoloured parts appear in it, they 44 müft be carefully pickt or cut out.”
The fal ammoniacum employed ought to be perfectly white and clean; and care fhould be taken, that the quickfilver be not fuch as is undulterate with lead, which may be known by putting a fmall quantity in a crucible, into tne fire, and obferving when it is taken out, whether it be wholly fublimed away, or have left äny lead behind it. The calcination may be belt performed in a coated glafs body, hung in the naked fire; and the body ftiould be of a long figure, that the other ingredients may rife fo äs to leave the coloured tin clear of them. The quickfilver, diough it be formed into Cinnabar along with the fulphur, need not be wafted; but may be revived by diftilling it with the addition of quick-lime j for which a very cheap and com- C c 2 modious method and apparatus may be found in a late treatjjfe on practical chemiftry, in- titled» The Elaboratory » &c.
There are fome other eparfier powders in imitation of gold» which are formed of precipitations of copper: but as they ace feldom ufed now for gilding, I fhflU defer fhewing the manner of preparing them, till I come to fpeak of bronzing, where they more properly occur. • *
Beiides thefe powders, the genuine leaf or Dutch gold may be ufed with the japanere gold fize, where a more Alining and glofiy effect is defired in the Riding: hot in that kind of gilding which is intended to be var* nifhed over, or to be mixed with other japan work or paintings in varnjfh, the powders are mod frequently employed*
The gilding with jupaners gold fize may be ptaftifed on aknoft any fubfiance whatever, whether wood» metal, lecher» or paper: and there is no further preparation of the work ' necefiary to its being gift, than the having the furface even and perfectly clean. f The manner of ufmg the japaners fize, | is to put a proper quantity of it, prepared as above dtredted, and mixt with the due pro* portion of oil of turpentine and vermilion, into a fmall gaily pot, or one of d}ofe tin vef- \ fels above defcribed, for containing the colours 1 when ufed for painting on varnifh j and ei- ’• ther to fpread it with a bfu£h over the work, • .. .where uhotefurfk® is to begiit; or to draw with it by means of a pencil the proper figure de- fired, avoiding carefully to let it touch any other parts; and then to fufier it to reft dU it be fit to receive the gold: which muft be diftinguifhed by the finger, in-the fame manner as with the fat oil; the having a proper clamminefs or fticky quality without being fo fluid as to take to thb nngef, being alike me criterion in both cafes. Being found of a proper drynefs, when the gold powders are to be ufed, a piece of the foft leather, called nzmjh- leather, wrapt round the forefinger, muft be dipt in the powder, and then nabbed Very lightly over the fixed week; or, what is much better; the powder may be fpnead bty a foft camel’s hair peocil; and the whole being covered, it muft be left to cky; and die loofe powder may then be cleared away from die gilded part, and collected; by means of a foft camel’s hair brafh. When leaf gold is ufed, the method of fixing muft be die fame as for the powders: but the point of due drynefs is very nice and delicate in thefo cafes; for the leaves muft be laid on while die matter is in a due ftate, odierwifo the whole of what is done mu(t be fized and gilt over again.
When more gold flze is roixt up with the od of turpentine, and vermilion, than can be ufod at one time, it may be kept by immerfing it under water tiU it be again wanted: which is indeed a general method of preferyiag all kind C c 3 of paint, or other fuch compofidons as contain oily fubftances.