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A brown or reddish pigment used in both oil and water colors, obtained from certain natural clays variously colored by the oxides of iron and manganese. It is commonly heated or burned before being used, and is then called burnt umber; when not heated, it is called raw umber. See Burnt umber, below.…

llow tint which is accompanied by a strong fluorescence, and its black oxide is used as a pigment in porcelain painting. Symbol U. Atomic weight 239.

found in any portion of the urinary passages or in the pelvis of the kidney. -- Urinary pigments, (Physiol. Chem.), certain colored substances, urochrome, or urobilin, uroerythrin, etc., present in the urine together with indican, a colorless substance which by oxidation is convertible into colored bodies.…

A yellow pigment identical with hydrobilirubin, abundant in the highly colored urine of fever, and also present in normal urine. See Urochrome.

A yellow urinary pigment, considered by Thudichum as the only pigment present in normal urine. It is regarded by Maly as identical with urobilin.

A reddish urinary pigment, considered as the substance which gives to the urine of rheumatism its characteristic color. It also causes the red color often seen in deposits of urates.

The posterior pigmented layer of the iris; -- sometimes applied to the whole iris together with the choroid coat.

A yellow pigment consisting of a compound of vanadium.

Vandyke. "His Vandyke dress." Macaulay. [Written also Vandyck.] Vandyke brown (Paint.), a pigment of a deep semitranssparent brown color, supposed to be the color used by Vandyke in his pictures. -- Vandyke collar or cape, a broad collar or cape of linen and lace with a deep pointed or scalloped edge, worn lying on th…

Any liquid with which a pigment is applied, including whatever gum, wax, or glutinous or adhesive substance is combined with it.

A green poisonous substance used as a pigment and drug, obtained by the action of acetic acid on copper, and consisting essentially of a complex mixture of several basic copper acetates.

Either one of two pigments (called blue verditer, and green verditer) which are made by treating copper nitrate with calcium carbonate (in the form of lime, whiting, chalk, etc.) They consist of hydrated copper carbonates analogous to the minerals azurite and malachite. Verditer blue, a pale greenish blue color, like t…

A bright red pigment consisting of mercuric sulphide, obtained either from the mineral cinnabar or artificially. It has a fine red color, and is much used in coloring sealing wax, in printing, etc.

painting, a kind of painting practiced by the ancients, under the name of encaustic. The pigments were ground with wax, and diluted. After being applied, the wax was melted with hot irons and the color thus fixed. -- Wax palm. (Bot.) (a) A species of palm (Ceroxylon Andicola) native of the Andes, the stem of which is…

A white pigment; as, Venice white.

Chalk prepared in an impalpable powder by pulverizing and repeated washing, used as a pigment, as an ingredient in putty, for cleaning silver, etc. Whiting pollack. (Zoöl.) Same as Pollack. -- Whiting pout (Zoöl.), the bib, 2.

replaces the normal color, as in certain parrots. It is commonly due to lack of the dark pigment which with yellow forms green.

The yellow pigment present in the inner segments of the retina in animals. See Chromophane.

An orange-yellow substance found in pigment spots of certain crabs.

A skin disease characterized by the presence of numerous small pigmented spots resembling freckles, with which are subsequently mingled spots of atrophied skin.