Page 265 - Chinese porcelains collected by Mr. and Mrs. Charles P. Taft, Cincinnati, Ohio, by John Getz

PORCELAINS WITH A BLACK GROUND

These porcelains, showing the reserved design separately treated in

light transparent and opaque enamel colors, form a characteristic class by
themselves. This mode of decoration, originating in China, has for cen-
turies been applied upon both biscuit and the purest white paste. It
may be stated that to fix the opaque black enamel, and to cover the
ground and to assimilate evenly, taxed the skill of the ceramists of early

periods, so that such products afford standards of excellence to all sub-
sequent eras and remain unrivaled to this day.

The dull black enamel color is developed under the action of a central

fire, of an intensity suited to the Risibility of the metallic oxides used.
To' produce the desired color white lead is employed, mixed with oxides

of cobaltiferous manganese and copper. In some pieces made in more
recent periods, the black enamel shows clear signs of a treatment to

reduce its natural brilliance in imitation of the older specimens.

The brilliant black enamel is obtained from oxides of manganese and

calcined cobaltiferous ores, with a mixture of certain proportions of fer-
ruginous earth, which gives the brown tinge called in China "Tzu-chm."

The number of metallic oxides used for other colors, viz., green, yellow,

amber-green, etc., although limited, were combined by the ceramists in
varying mixtures, so as to obtain many contrasting tints of special beauty
and quality.

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