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Pale Chrome And Deep Chrome Are Chromates Of Lead In Which The








latter metal more or less exists, according to the paleness or depth of
the colour. Of modern introduction, they are distinguished for their
brilliancy, their opacity and body, and their going cordially into tint
with white, both in water and oil. Owing, however, to a harshness and
hardness of tone for which they are peculiar, a coarse and disagreeable
effect is apt to be produced by their use. In general, they do not
accord with the modest hues of nature, nor harmonize well with the
softer beauty of other colours. Rivalling the cadmiums in brightness,
they are wanting in the mellow richness which belongs to the deeper
varieties of those pigments, as well as in their permanency. Although
they resist the sun's rays for a lengthened period, after some time they
lose their original hue, whether employed alone or in tint, and may even
become black in impure air. Upon several pigments they produce serious
changes, ultimately destroying Prussian and Antwerp blues, when
compounded therewith in the composition of greens, &c. Ranging from
lemon to deep yellow, in oil, provided the atmosphere be good, the
chromes may be found comparatively durable; but, on the whole, the
artist cannot trust to them his reputation as a colourist.

The chromates are often mixed with sulphate of lead, as well as with the
sulphates of baryta and lime. The presence of the first is especially
objectionable, as increasing the tendency of the yellows to be blackened
by foul gas. The sulphates of baryta and lime, however, are sometimes
formed in the process of preparation, in which case they are rather an
advantage than otherwise; inasmuch as they not only lend a softness to
the colour, but decrease the proportion of leaden base, and consequently
the tendency referred to. We may remark, indeed, with respect to
pigments, that it is difficult in many instances to say where
manufacture ends and adulteration begins. A substance may be present
which, although not absolutely essential to the colour itself, has been
legitimately employed to impart a desired quality, or a certain tint.

TTITLE COLOGNE YELLOW

Is a cheap inferior chrome yellow, unfit for artistic purposes, and
consists of twenty-five parts of chromate of lead, fifteen of sulphate
of lead, and sixty of sulphate of lime.

TTITLE JAUNE MINERALE

Is prepared in Paris, and differs in no essential particular from
ordinary chromate of lead, except in the paleness of its colour. The
chrome yellows have also obtained other names from places or persons,
whence they have been brought or by whom they have been made. Another
lead yellow, not a chromate, has likewise been called jaune minerale.

TTITLE CITRON YELLOW

Is chromate of zinc, a bright pale lemon-like yellow, slightly soluble
in water. It is not affected by foul gas, but does not preserve its
colour on exposure to light and air, or even when kept in a book. In
contact with organic substances it is apt to turn green. Compounded,
especially for foliage tints, this yellow is eligible; but if purity of
hue be desired, it should certainly not be employed alone. In this
chromate, as in many others, the affinity of the chromic acid to the
base is small; the former is liable to separate from the latter, and, by
deoxidation, to become converted into green oxide of chromium.

TTITLE GALLSTONE

Is a deep-toned gorgeous yellow, affording richer tints than most other
yellows, but it cannot be depended on for permanency, and therefore is
seldom employed. Its colour is soon changed and destroyed by strong
light, though not subject to alteration by impure air. In oil it is
ineligible. A true gallstone is an animal calculus formed in the
gall-bladder, chiefly of oxen; but the pigment sold under that name is
often replaced by a substitute, resembling the original in colour, but
of greater stability.

TTITLE GAMBOGE,





Next: Sometimes Designated Drop Gum And Variously Written Gamboge

Previous: Also Called Jaune Minerale Jaune De Cologne Or Cologne Yellow



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