CLASS III. Of yellow colours.
Of King s yellow.
King's yellow is a pure orpiment, or arfenic coloured with fulphur. It is ufed for painting in oil and varnifh : and is of an extreme bright colour, and when good a true yellow j it will likewife Hand well being ufèd alone: but when mixed with white lead, and feveral other pigments, its colour flies or changes. On this account, and for the addi-tional reafons of its being efteemed a poifbn, and having a moft naufeous fmell, it is rejeét-ed by many; but others find too much ad-vantage m its great brightnefs, as well in the ufé of k as a yellow, as when mixed with blue pigments to form a green, not to have recourfe to it on feme occafions.
This pigment muft be prepared by mixing fblphtrr and arfenic by fublimation, which may be done in the following manner.
1 « Take
“ Take of arfenic powdered and flowers of “ fulphur in the proportion of twenty of the “ firft to one of the fécond : and having put “ diem into a fublimer, fublime them in a “ fand-heat, with ftich a furnace as is de- fcribed p. 20, according to the general di- *' regions given p. 30. The operation be- ** ing over, the king’s yellow will be found in the upper part of the glafs j which muft be <c carefully feparated from any caput fnortuum “ or foul parts that may be found in the glafs “ with it. It muft be afterwards reduced to *c an equal powder by lévigation.”
It may likewife be obtained from common °rpiment, by fubliming it, inftead of the àr- fônic and fixlphur, in the famé manner.
The king’s yellow may be rendered warmer, that is more inclined to orange, by increafing the proportion of the arfenic ; or the contrary effect may be produced by diminishing it.
King’s yellow cannot be adulterated without diminishing its brightnefs : and therefore that which is belt in this refpeét may be efteemed good in others. Coolnefs, or the being free from red, is likewife a merit.
Of Naples yellow.
Naples yellow is a warm yelloW pigment rather inclining to orange, but in a very minute degree. It is feldom ufed but in painting with oil : where it is generally found to fend well j but, if it touch iron along with
the lcaft watery moifture, it will be changed by it. As it is brighter than moll yellows ufed in oil, and indeed than all at prefent in ufe, except the king’s yellow, it is much received into pra&ice. It has been fuppofed to be a native earth, and is faid to be found in the neighbourhood of Naples ; but this is dubious, as me different parcels of it vary too much from each in fpecific qualities to allow the fuppofition of their being native earths of the fame kind, at leaf! with reipett to fuch as are to be obtained from our {hops ; for I have met with lome that was of a very différent compofition from the common. The uncertainty with regard to die genuinenels renders this pigment lefs valuable, as it is lefs to be depended upon with re- fpedt to its holding its colour. Whether, however, it is an earth that is at prefent generally fbphifficated, or what the preparation of it is, we ai e at prefent ignorant of, as it is brought from abroad j and this makes it more difficult to give marks of its genuinenefs ; which may therefore be beft: gathered from its appearance and manner of mixing with the oil, in which the more adulterate kinds differ from the common.
Though Naples yellow .is of a gritty texture, yet it is beff: to ufe it as it is obtained, and only grind it with the oil ; for it does not well bear lévigation with water. But if fuch lévigation be neverthelefs pra&ifed on it, the greateff care muff: be taken to employ an ivory l'patula in the place of a pallet knife -, which
would
would certainly injure the colour, if it were touched with it while wet ; ,and even when moiftened with oil, the iron is in ibme degree injurious to it.
Of yellow oker.
Yellow oker is a mineral earth, which is found in many places, but of different degreed of purity. When free from other earths and heterogeneous matter, it is a true yellow'of mor derate brightnefs: and, as its textbre fuits it for all kinds of painting, and ttu£ it will never fly in the leaft, it is a very valuable colour with refped: to its utility, though of low price.
There is no other preparation of yellow oker neceflary than levigation : and for nicer purpofes wafhing over ; to undergo which its texture is extremely fuitable. .
The goodnefs of yellow oker may be diftin- guifhed by the brightnefs and fulnefs of its yellow colour; and if it be bright, it cannot be too cool. But as it is not unufual to mix it with Dutch pink, and fet an extraordinary price upon it as being extremely good, that impofition muft be guarded againft ; which may be done by heating it to the degree that will turn paper brown; which if it be genuine will make little or no alteration in it; but if it be adulterated in this manner will give an ap* parent foulnefs to it.
Of Dutch pink.
Dutch pink is a pigment formed of chalk,
coloured with the tinging particles of French berries or other vegetables.
It is principally ufed for coarfer purpofes in water j not bearing well to be worked in oil:
nor can it be depended upon with regard to its Handing fo as to be fit for paintings of any confequence.
There are a variety of methods of preparing Dutch pink:
bait the following is very cheap and eaiy; and makes a molt beautiful pigment.
“ Take of French berries one pound, and ** of turmeric root powdered four ounces; boil ** them in a gallon of water two hours ; and “ then ftrain off the tincture through flannel, “ and boil it again with an ounce of alum till tc it be evaporated to one quart. Prepare in the mean time four pounds of chalk, by “ wafhing it over, and afterwards drying it: ** and mix the chalk with the tin&ure, by “ grinding them together: and then layout the ** Dutch pink thus made to dry on boards.” Dutch pink is fometimes prepared in the fame manner with ftareh and white lead.
The goodnefs of Dutch pink confifts in its being of a full gold coloured yellow, and very bright.
Of Englijh pink.
English pink is only a lighter and cottier kind of Dutch pink.
Of light pink.
Eight pink is of two kinds, the one the lame with the Dutch pink, only with greatly lefe colour: the other the fame with the brown pink that is, transparent in oil, but with Ies colour.
The firft kind like the Dutch pink is only fit for ufing in water; and there, likewile, only in paintings where the holding of the colour is not of great confequence.
The other is by forne ufed in oil paintings» in the lame manner as brown pink: its tran
-fparency making it have a good effect in Shades for fome purpofes; but it is not a judicious practice: for all thefe colours formed of vegetables are very uncertain with refpedt to their Handing; and the native earths or prepared okers properly managed will anfwer equally die fame ends.
The preparation of the tfirft kind of light pink may be in the fame manner as that of the Dutch pinkj only diminishing the proportion of the French hernes and turmeric to one half.
The light pink may be prepared in the following manner.
“ Take of French berries one pound. Boil them with a gallon of water for an hour: and then ftrain them off; and add two pounds of t£ pearl-afhes, diflolved and purified by filter- ing through paper. Precipitate with alum diflolved in water, by adding the folution gradually, lb long as any ebullition fliall ct appear to be raifed in the mixture. When <c the fediment has thoroughly fubfided, pour *€ off the water from it; and wafh it with <c feveral renewed quantities of water, pro- ceeding as has been before directed in the <c cafe of lake, &c.; and then drain off the remaining fluid in a filter with a paper tC covered with a linnen cloth; and laftly dry it on boards in fmall fquare pieces.”
It may be likewife prepared from fuftic wood, yellow fanders, and feveral other vegetable fubftances, which afford copioufly a yellow tinge.
The goodnefs of light pink lies principally in its brightnefa and tranfparency: and, when defigned for the fhops, care (hould be taken that it do not fatten in the oil; which will happen, if the falts be not thoroughly wafhed out of it.
Gumboge.
Gumboge is a gum brought from the Eaft Indies. It diflolves in yellow to a milky con- flftence, and is then a bright light yellow. It is ufed only in water : but there is of great fervice;
gf fervice, being the principal ; or, indeed, al* moil the only yellow commonly employed.
* Gamboge requires no preparation, but dik iolves immediately on rubbing it, with the ad-dition of water.
The goodriefs of gamboge may bd diftin- guilhed by its appearance while in the ftate of a gum of a deep warm bright colour: and the more it approaches to tranlparency the better.
Of mafticot.
Mafticot is flake white, or white lead, gently calcined; by which it is changed to a yellow of lighter or deeper teint, according to the degree of calcination. It is not greatly ufed at prefent the colour not being very bright: but as it will ftand perfectly in oil; and in water, as well as flake white, or white lead, it certainly might be ufed for many purpofes ; as it works with the pencil better than moft other pigments.
It may be prepared by putting the flake white, or white lead, on an earthen or Hone dilh before a ftrong fire j and continuing it there till the colour be fufficiently yellow; each fide of the plate being put next to the fire in its turn, that the whole of the mafticot may be equally calcined : or the matter to be calcined may be put into a crucible; and the crucible placed in a moderate heat in a common fire; care being taken to remove it as loon as the mafticot appears of a proper colour; which
H mult
muft be diftinguilhed by taking a part of it out, for the colour does not fhew itfelf properly while the matter is hot. The calcination being finilhed, the parts which are of the teint wanted muft be picked out from the reft, and put together : for, with the greateft ' care, it is difficult to calcine the whole equally ; and confequently to avoid rendering fome parts of a deep yellow or orange.
There is no further preparation neceflary for the ufing mafticot either in oil, or water painting, except the grinding it with the vehicle.
Common orpiment.
Common orpiment is a foffile body com- pofed of arfenic and fulphur, with a mixture frequently of lead, and fometimes other metals. It was formerly ufed as a yellow in painting ; but at prefent is very feldom employed in its unrefined ftate, unlefs to ccdour the matted bottoms of chairs or other fuch coarfe work. When purified by fubliming, it becomes the king’s yellow, of which we have before fpoken. It is of a pale yellow colour, and might be ufeful for feversd pur- poles, if its naufeous fmell, and fuppofedly poifonous quality, did not make the meddling with it difagreeable, particularly in oil, where its bad fcent is greatly increaled. The good- nefs of orpiment confifts in the brightness and ftrength of its colour; and the warmer, or
rather
rather the lefs inclining to green, the better it is for the purpofes of painting.
Of gallftones.
Gall ftones are concretions of earthy matter and bile formed in the gall bladder, or bile duCts of beafts. It is ufed by thbfe, who know the fecret of its excellence, in water : with which being rubbed, and treated as gamboge, it becomes a deep warm yellow, that foi its brightnefs and dark fhade, when not too thin fpread, as well as holding its colour, is very Valuable.
As the gall ftones are not always to be procured, a fictitious kind may be prepared; which will greatly anfwer the fame purpofe. They may be made in this manner.
“ Take a quart of the bile of oxen, as frefh as poffible. Put it into a proper “ pewter veflelj and fet it to boil in balneo “ mariae ; having added to it a quarter of an <c ounce of clear gum Arabic. Evaporate the “ whole to about an eighth; and then remove it “ into a China cup orbafon of proper fize; and “ evaporate it to drynefs; collecting it into a “ mafs as it becomes of a ftiff confidence.”
This may be ufed as the gall ftones: and, being more tranfparent, will be found of very great advantage in water painting.
Terra de Siena unburnt,
Terra de Siena, as we have faid before, fpeaking of it as a red when calcined, is a native ochrous earth, brought from Italy. In its uncalcined date it is a deepilh warm yellow, and but flightly tranfparent either in oil or water. It is much lefs ufed uncalcined than calcined : but, neverthelefs, as it is a deeper yellow by many degrees than any of the other okers, and of a fuperior brightnefs, it might be ufed with advantage, as it will Hand equally with the bed.
When terra de Siena is ufed uncalcined, it ought "to be extremely well levigated and washed over j otherwife it is apt to lie heavy in the oil; which is probably die chief reafon why it is fo feldom ufed in an uncalcined Hate; though as much wanted for fome purpofes as the calcined for others.
Turpetb mineral.
Turpedi mineral is a preparation of mercury, by calcining it together with oil of vitriol. It is an exceflive bright true yellow, of a great body like vermilion; and will Hand equally well with that: and it works likewife with oil or water much in the fame manner. Thefe qualities render it very valuable for many purpofes ; as it is much brighter than any other -yellow ufed in oil, except king’s yellow i
low ; and is free from the naufeous fmell of that pigment; as well as cooler. This coolnefs, and its bearing to be mixed with Pruflian blue, from whence a much finer green can be produced by it than from the king’s yellow without ultramarine, give it, on the whole, greatly the preference. It has not, however, that I know of, been ufed in painting by any except thofe to whom I have recommended it: and •who, on trial, have found it anfwer to what I have here laid of it.
The turpeth mineral may be beft prepared In the following manner.
“ Take of pure quickfilver, and oil of vitriol, each fix pounds. Put them into a rectort; to which, being placed in the fand- cc bath, fit on a receiver; and diftill them with tc a ftrong fire, while any fumes appear to rife £C into the receiver; urging it at laft with as ct great a heat as the furnace will bear. When t£ die retort is again cold, remove it out of the ft fand bath : and, having broken it, take the “ white mafs, which will be found at the bot- “ tom of it, and break it to a grofs powder; “ and, having put it in a glafs mortar, pour “ water on it; which will immediately con-vert it to a yellow colour. Let it then be thoroughly ground in this mortar, with wa-ter, and afterwards wafhed with feveral fuc-ceflivc quantities. It mull: then be thoroughly “ well levigated on a ftone, and dried.”
The turpedi mineral may be had from the (hops of any chemifts or dealers in medicines; but is not at prefent in thofe of colourmen. As it is now to be procured, it requires a previous levigation in water before it be ufed being for the moil part, (though faultily,) levigate for the ufes of the medicine only in a very flight manner. The marks of goodnefe in the turpeth mineral-are the brightnefs of the colour; and its fulnefs or warmth: for as it never inclines more to the red than a trufc yellow, the lefs it verges on the green, the better it confeqaently is for the purpofes of painting.
Of the yellow wafh from the French berries.
This is a folution of the gum of the French berries in water. It is ufed as a waihing colour in water painting: and as it may be made of almoil any degree of deepnefs, and is pretty bright, it is applicable to many material pur- poles, fince nothing can be made of die gamboge but light tints. This colour will Hand allb extremely well, and being more diluted or laid on thicker, will in confequence of its tran- fparency, give a variety of fhades.
The yellow-berry-wafh may be thus prepared,
“ Take a pound of the French berries, and “ put to them a gallon of water, with half an “ ounce of alum, boil them an hour in thti “ pewter vefi'el defcribed p. 24, and then fil- “ ter off the fluid, (through paper if it be “ dpfigned for nicer purpofes, or flannel for 1 “ more
more ordinary.) Put them again into the Cf boiler and evaporate die fluid till the colour ** appear of the ftrength defired; or part may “ be taken out while lefs ftrong, and the reft cc evaporated to a proper body.”
The goodnefs of the French berries may be «iiftinguifhed by their appearing large, plump, and heavy j and if they have thefe qualities, the darker they appear the better: but unlefs they are large and plump, the darknefs may only arife from their being gathered before they are duly ripe.
Turmeric waft.
The turmeric walh is the gum of the turmeric root diflolved in water. The qualities and ules of it, are much the lame as the yellow berry-walh ; only it is a brighter and cooler yellow ; but fo ftrong a tincture cannot be made of it in water as of the French berries.
It may be alfo prepared in the fame manner as the former.
Of tincture of faffron.
Tincture of faffron is ufed as a yellow wafh with water colours. It is made by pouring hot water on the beft Englifh faffron in a proper phial or other veflel in which fhould be placed for feme time in a heat next to that which would make the water boil: and the tincture fhould
then be filtered from the dregs through a piece; of linnen cloth. The proportion of the faf- fron to the water muft be regulated by the intention of having the colour deeper or paler. This tindture is a fine warm yellow; and when very ftrong makes a very proper lhade for the gamboge or other light yellows that are bright: and it will Hand equally well with any of the vegetable tindtures.