VIEW THE MOBILE VERSION of www.pigment.ca Informational Site Network Informational
Privacy
  Home - Chromatography - Color Value - Aesthetics - Photography


/








White Lead {Lead. / Sulphide of Lead (Black.)
{Carbonic Acid.

Such is the theory of the reaction which might take place, but which, as
far as our own experience goes, does not. Some deep cadmium yellow which
we ourselves prepared was intimately mixed and ground with an equal
quantity by weight of Cremnitz white, and an oil rub of the compound
laid upon a tile. Having placed the latter on a shelf in the laboratory,
we watched from week to week to see if any approach to blackness
occurred, any diminution in the beauty of the tint; but could perceive
none. Hence, while admitting the possibility of the colour being
damaged or destroyed in the case of an inferior and spurious article, we
conclude that an unadulterated cadmium yellow, containing no free
sulphur, neither injures, nor is injured by, white lead, and may safely
be used therewith. At the same time, the artist should be warned to
satisfy himself of the genuineness of his pigment, or otherwise to
employ the white of zinc, at least as a medium of intervention.

A good sample of cadmium yellow may rather advantageously than otherwise
be compounded with white lead, for we have found that a mixture of equal
parts by weight of the two will bear an atmosphere of sulphuretted
hydrogen that completely blackens the white alone.

With all the sulphides of cadmium a steel palette knife is best avoided.

TTITLE PALE CADMIUM.

The cadmium yellow so-called, is not strictly pale, but pale only when
compared with the preceding. It is, in fact, a full rich colour,
brilliant and permanent, but without that tendency to orange which
distinguishes the deep. For some purposes, when a warm tone is not
required, such a tint is preferable. In water, especially, where
delicacy of colouring can be carried to a greater degree of refinement
than in oil, these differences of hue are important. In the first
medium the faint washes show with a clearness which is not so apparent
in the last, and the most subtle gradation of tone tells with a force in
some measure lost in oil. As a consequence, the colour of the lightest
tints in the distance must be as true as that of the deepest shades in
the foreground, and hence the warmth or coldness of the pale washes of a
pigment should be duly considered.

Pale cadmium yellow with or without aureolin, is adapted for golden
sunsets, and yields with French blue a beautiful sea-green.

TTITLE LEMON CADMIUM.

Very pale cadmium yellows are not permanent, and lemon cadmiums are
decidedly fugitive. Being, like the deep and 'pale' varieties,
sulphides, they are of course unaltered by sulphurous gas; but they will
not stand exposure to light and air, or even to light alone. Some which
were submitted in an air-tight bottle to the action of light gradually
whitened next the glass. Yet they were almost identical in composition
with the deepest and most orange hues, and might have reasonably been
presumed stable. Repeated experiments, however, both with samples of our
own making and of others' manufacture, have shown that for a cadmium to
be durable, it must be of a full, rich, comparatively deep yellow; and
that any paler product than the 'pale' alluded to cannot be depended
on. It is true that a light or lemon tint will fade quicker in water
than in oil, but a colour which is fugitive in the one vehicle cannot be
regarded as eligible in the other. From a somewhat long acquaintance
with cadmiums, we have derived the opinion that their stability rests
much on the mode of preparation, and that an amount of heat is needed





Next: Sufficient To Make The Sulphur Bite Into The Base This Opinion

Previous: Cadmium Yellow {cadmium Carbonate Of Cadmium (white)



Add to del.icio.us Add to Reddit Add to Digg Add to Del.icio.us Add to Google Add to Twitter Add to Stumble Upon
Add to Informational Site Network
Report
Privacy
SHAREADD TO EBOOK


Viewed 1920