PIGMENT. 427 
veflels and dried for ufe. A neceflary precaution, in the 
preparation of this colour, is to avoid the ufe of iron, the 
contaft with this metal imparting to it a dirty and fome- 
times a greenilh tint; whence alfo, in grinding the colour 
on the (tone, a fpatula of ivory is to be made ufe of for 
the purpofe of collecting the mafs. The Naples yellow is 
principally ufed for painting in oil, it poffe fling much 
more richnefs and brilliancy than the ochres, maflicot, 
or orpiment, and being far more durable. It may alfo be 
advantageoufly applied for enamel-painting. Chambers, 
art. Giallolino. 
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. It is made by boiling one pound of French 
berries and four ounces of powdered turmeric-root in 
a gallon of water for two hours, and then (training off the 
tincture through flannel, and boiling it again with an 
ounce of alum, till it be evaporated to one quart. Pre¬ 
pare in the mean time four pounds of chalk, by walking 
it over, and afterwards drying it; and mix the chalk with 
the tinfture, by grinding them together, and then dry it 
on boards. It is fometimes prepared in the fame manner 
with (larch and white-lead. Its goodnefs confifts in its 
being of a full gold-coloured yellow, and very bright. 
Englilh pink is only a lighter and coarier kind of 
Dutch pink; and may be prepared in the fame manner, 
the quantity of chalk being increafed in proportion, as 
it is intended tp be inferior to the Dutch. 
Light pink is of two kinds; the one being the fame 
with the Dutch pink, only with much lefs colour, fo that 
the proportion of the French berries and turmeric muft 
be leffened to one-half; the other is the fame with the 
brown-pink, that is, tranfparent in oil, but .with lefs co¬ 
lour. It may be prepared by boiling one pound of 
French berries in a gallon of vt'ater, for an hour, and 
adding to the (trained fluid two pounds of pearl-a(hes, 
diflolved and purified, by filtering through paper; then 
precipitate w'ith alum diifolved in water, by adding the 
folution gradually, till the ebullition ceafes. 
Maflicot is prepared by calcining white-lead till it 
affumes a yellowifn colour. It is not apt to change ; but 
the colouris fo dull, that it is feldom ufed either in oil or 
water. 
Common orpiment is a pretty bright greenifh-yellow, 
prepared by fublimingarfenic with fulphur. Its naufeous 
fine]], which is greatly increafed by grinding in oil, makes 
it very difagreeable; nor does it keep its colour for any 
length of time. That kind of orpiment lead inclined to 
green is to be preferred for the purpofes of painting. 
Yellow ochreand terra di Sienna are ferruginous earths, 
capable of becoming red by calcination. Green vitriol 
precipitated by lime may be advantageoufly fubftituted 
for either of them. See Chemistry. 
Turbith mineral is but little ufed in painting, though 
its fine yellow colour feems greatly to recommend it. 
This preparation is in all probability very durable; and 
fliould feem therefore worthy of a preference either to 
■ king’s or Naples yellow. 
Gamboge is a paint that can only be ufed in water, 
and is the mod common yellow made ufe of for colouring 
maps, &c. but for tiiis it is not very proper, being neither 
quite tranfparent nor very durable. 
The leaves of many kinds of herbs and trees give a 
yellow dye to wool or woollen cloth that has been pre- 
vioufly boiled with a folution of alum and tartar. Weld, 
in particular, affords a fine yellow, and is commonly 
made ufe of for this purpofe by the dyers, and cultivated in 
large quantity in fome parts of England. There is no 
colour for which we have fuch plenty of materials as for 
yellow. M. I-Iellot obferves that all leaves, barks, and 
roots, which on being chewed difeovera (light adringency, 
as the leaves of the almond, peach, and pear, trees, a(h- 
bark, (efpecially that taken off after the fir ft rifing of the 
fap in the fprmg,) the roots of wild patience, See. yield 
durable yellow's, more or lefs beautiful according to the 
length of time that the boiling is continued, and the 
proportions of alum and tartar in the preparatory liquor: 
that a large quantity of alum makes thefe yellows ap¬ 
proach to the elegant yellow of weld : that, if the tartar 
is made to prevail, it inclines them to an orange: that if 
the roots, barks, or leaves, be too long boiled, the yellow 
proves tarni(hed,,gnd acquires (hades of brown. 
A chemift of Copenhagen, in 1818, fucceeded in ob¬ 
taining a good yellow dye from potatoes. Gather the 
tops of the potatoes when ready to flower, prefs the juice, 
and mix it with more or lefs water; let the cloj:h (whe¬ 
ther of W’ool, fiik, cotton, or flax) remain twenty-four 
hours; then rince it in fpring-water, and it comes out a 
bright yellow; this yellow may be converted into a bril¬ 
liant and lading green, by plunging the cloth, thus 
tinged, into a veffel of blue dye. 
6. Green. —The only Ample green colour that has a 
tolerable degree of brightnefs is verdigris, or prepara¬ 
tions of it. This, however, though a very beautiful 
colour, is far from being durable. It is improved in 
colour, though not in durability, by diffolution and 
crydallization in diddled vinegar, in which date it is 
called dijlilledverdigris. A more durable water-colour is 
made by diffolving the verdigris in cream of tartar, or 
rather the pure tartaric acid ; but in oil this is found to 
be equally fugitive with the verdigris itfelf. 
Compound greens are either made of Pruffian or fome 
other blue, mixed with yellow; but, in whatever way 
thefe colours can be compounded, the beauty of the 
green produced is greatly inferior to diddled, or even 
common, verdigris. The tartaric folution of verdigris, 
mixed with a little gamboge, is the bed tranfparent green 
water-colour we have had an opportunity of trying; and 
a mixture of Pruflian blue and turbith mineral is proba¬ 
bly the bed opaque one. 
Sap-green is a Ample colour, but exceedingly inferior 
to diddled verdigris, or even to the tartaric folution of 
verdigris with gamboge. It is prepared from the juice 
of unripe buckthorn-berries evaporated to the confidence 
of a gum. Its green colour is greatly inclined to yellow. 
A kind of compound green has been fometimes ufed, 
called Pruffian green, which confifts only of Pruffian blue 
and yellow ochre. It has no beauty, nor is it durable. 
It is prepared as Pruflian blue, only not pouring on any 
muriatic acid to diffolve the ochreous fediment which falls 
at the fame time. 
Another green fometimes ufed is called ter re verte. 
This is a native earth, probably impregnated with copper. 
It is of a bluifli-green colour, much of that tint called 
fea-green. It is gritty, and therefore muft be well levi¬ 
gated before it is ufed. Its colour is durable, but not 
very bright. 
7. Blue. —The blue colours are ultramarine, Pruffian 
blue, verditer, fmalt, bice, and indigo. Of thefe the 
ultramine is the fined, but its great price hinders it 
being much ufed. It is a preparation from lapis lazuli; 
is an exceeding bright colour, and never fades, with what¬ 
ever fubftance it is mixed. It is now, however, in a 
great meafure, fuperfeded by Pruflian blue, to the difad- 
vantage of painting in general ; as Pruffian blue, though 
very beautiful, is far from being durable. For an account 
of its preparation, fee the article Chemistry, vcl. iv. p. 
300. It will be fufficient here to obferve, that it io to be 
accounted of the bed quality when it is deep, bright, 
and not inclined, to purple. It ought to be tried by 
mixture with white lead, as the brightnefs of the colour 
will appear much more when diluted than when concen¬ 
trated in the lumps of the blue itfelf. 
With regard to liquid colours for maps, See. we appre¬ 
hend there can be very little difficulty in preparing all 
the poflible varieties of them. The only colour with 
which-there can be any difficulty is blue; but the common 
folution of indigo in alkalies or acids may be made to 
anfwer this purpofe, though, on account of their ftrongiy 
(aline 
