Called Also Mineral Yellow Is Found In Most Countries And Abundantly





in our own. It differs much both in constitution and colour, ranging

from a tolerably bright though not vivid yellow to a brown-yellow, and

is generally of a warm cast. Its natural variety is much increased by

artificial dressing and compounding. The best yellow ochres possess no

great force, but as far as they go are valuable pigments, particularly

in fresco and distemper, being neither subject to change by ordinary

light, nor sensibly affected by impure air, or the action of lime. By

time, however, and the direct rays of the sun, they are somewhat

darkened. Like other ochres, they may be safely used in admixture with

pigments which are themselves permanent. With carmine and the cochineal

lakes, or intense blue, the ochres are best not employed.



The impunity with which yellow ochre bears foul gas is one of its many

recommendations. No immediate effect whatever is produced by

sulphuretted hydrogen, and only a slight dirty brown tint is imparted

by its prolonged action. This discolouration a short exposure to air and

light quickly removes. By keeping the ochre sufficiently long in contact

with sulphide of ammonium a jet black is obtainable, but a rub of it in

a moist unwashed state completely regains its yellow hue in a day or so.

Hence, yellow ochre compounded with pigments which suffer from an impure

atmosphere doubtless acts as a preservative agent.



Yellow ochre is usually employed in the distance and middle ground of a

landscape. It possesses a slight degree of turbidness, and is esteemed

for this property, which is considered to give it a retiring quality. By

admixture with Antwerp blue or indigo it affords a fine range of quiet

greens, also a very serviceable yellowish drab with Vandyke brown. The

ochre is valuable in warm skies, the sails of ships and boats, sandstone

rocks and cliffs, buildings, hay, sheep, &c. It does not compound kindly

with any of the cold colours, and should therefore be used as a wash

over others that are dry, when required to qualify their tints.



TTITLE ROMAN OCHRE



Is rather deeper and more powerful than the preceding, as well as more

transparent and cool in tint. In other respects it is similar, and forms

with Antwerp blue and indigo a like excellent range of greens. We may

observe, however, that as indigo is not a permanent pigment, the colours

it yields by admixture cannot be durable as far as the blue is

concerned. Roman ochre and brown madder are admirably adapted for red

sails, and autumnal effects of foliage.



TTITLE BROWN OCHRE,





Called Also Mineral Yellow Has Improperly Been Classed As An Called Also Spanish Ochre Is A Very Bright Yellow Or Roman Ochre facebooktwittergoogle_plusredditpinterestlinkedinmail

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