Yellow Orpiment, Or Yellow Arsenic, is a sulphuretted oxide of arsenic, of a beautiful, bright, and pure yellow colour, not extremely durable in water, and less so in oil: in tint with white lead it is soon destroyed. It is not subject to discoloration in impure air. This property is not, however, sufficient to redeem it with the artist, as it has a bad effect upon several valuable colours, such as Naples yellow; and upon the Chromates, Massicot, and Red lead, and most other oxides and metallic colours: but with colours dependent upon sulphur or other inflammables for their hues it may be employed with less danger, and was probably so employed by the old painters, with ultramarine in the composition of their greens; and is well suited to the factitious or French ultramarines. Although this pigment is not so poisonous as white arsenic, it is dangerous in its effect upon health. Yellow orpiment is of several tints, from bright cool yellow to warm orange, the first of which are most subject to change; and it has appeared under various forms and denominations: - these seem to have been used by several of the old masters, with especial care to avoid mixture; and as they dry badly, and the oxides of lead used in rendering oils drying destroy their colour, levigated glass was employed with them as a dryer, or perhaps they were sometimes used in simple varnish. They are found in a native state under the name of zarnic or zarnich, varying in colour from warm yellow to green. But orpiment, in all its varieties, powerfully deprives other substances of their oxygen, and therefore is subject to change, and to be changed by, every pigment whose colour depends on that element, and more especially all metallic colours: if employed, they must therefore be so in a pure and unmixed state. See Orange Orpiment.

We know that Mengs and Sir Joshua Reynolds employed them in their practice, as did also Sny-ders, John Van Huysum, De Heem, and other painters of still life, sometimes successfully, and sometimes otherwise; but we are far from recommending them as eligible pigments.

2. King's Yellow

Yellow orpiment has been much celebrated under this name, as it has also under the denomination of -

3. Chinese Yellow

Chinese Yellow, which is a very bright sulphuret of arsenic, brought from China.

4. Arsenic Yellow

Arsenic Yellow, called also Mineral Yellow, is prepared from arsenic fluxed with litharge, and reduced to powder. It is much like orpiment in colour, dries better, and, not being affected by lead, is less liable to change in tint. It must not be forgotten that it is poisonous.