DOI Page / Citation link:
https://doi.org/10.11588/diglit.20658#0326
312
COLOURING SUBSTANCES.
in the following manner :—Four ounces of finely pulverised cochineal are to be put into fonr
or six quarts of rain or distilled water that has been previously boiled in a pewter kettle. These
are again boiled together for six minutes more, adding according to some practitioners two
drachms of pulverised crystals of Tartar. Next add eight scruples of Roman alum in powder;
and the whole is kept on the fire one minute longer. As soon as the gross powder has subsided
and the decoction has become clear it is to be carefully decanted into large cylindrical glasses,
covered over and kept undisturbed, till a fine powder is observed to have settled at the bottom.
The liquor is then poured off from this powder which is to be gradually dried; and from the
liquor, which is still much coloured, the rest of the colouring substance may be separated by
means of the solution of tin, when a carmine little inferior to the former will be obtained.
Crocus Martis is obtained in different ways, but always with a solution of iron to be afterwards
precipitated. It may be made by calcining the mars yellow, in the same manner as the burnt-
terra di Sienna is procured from the raw mineral of that name : it is then dearer than that usually
sold in the shops, but it is lighter, more transparent, and more pleasant to use. This colour is
easy to work with, and unites perfectly with all others. From all martial ochres a red more or
less deep, may be obtained, by exposing them to the action of fire : but the quality is greatly
inferior to that obtained from martial vitriol.
Minium or Red Lead is lead calcined until it acquires a red colour, by exposing it with a large
surface to the fire. It may also be made from litharge, which is a semi-vitrified oxyde of lead,
obtained by keeping a stream of air upon lead when in fusion, and generally procured in the
course of separating silver from lead ; but the minium in this way is not so good as when
obtained from lead in its metallic state. Red lead is very apt to turn black, both in water and
oil, and is therefore seldom used but for coarse works.
Vermilion or Cinnabar is a bright scarlet colour, procured by combining mercury with sulphur.
Cinnabar is found in a natural state in many parts of Europe; it is then compact and generally
of a colour resembling brick-dust: when it is reduced to powder it approaches somewhat to
carmine, being then called vermilion. The goodness of cinnabar may be known bv observing
the colour of the flame arising from it, when placed upon red hot ashes; if the flame be blue,
bordering upon violet, and no smell arise from it, the cinnabar is of a good quality. Artificial
Cinnabar is a mixture of mercury and sulphur sublimated by fire, and ought to be of a fine deep
red. This sort of cinnabar is often preferred to the natural. To procure the vermilion, grind
the cinnabar with water on a piece of porphyry, which diminishes the intensity of its colour and
produces a beautiful red. After this grinding dilute it in more water, and letting it stand for a
short time, pour off the water while it is still loaded with colour, by which means you will
separate the finer from the coarser parts of the vermilion. The water being again allowed to
settle completely the pure vermilion is obtained, and the coarse parts are again ground and
washed as before. To have the vermilion as pure as may be, you should grind it afterwards
upon porphyry, with child's water or brandy, and let it dry in the shade; to give it a lighter
tone you may mix with the liquid a little saffron. A very beautiful vermilion colour may be also
obtained by mixing powdered cochineal with burnt alum, and quenching them in rose water.
The colour brought from China is superior to any other, but it is apt to turn black.
Saturnine Red is prepared nearly in the same manner with minium or common red lead, of
which it is only a variety : and is afterwards washed repeatedly in large quantities of distilled
water,
COLOURING SUBSTANCES.
in the following manner :—Four ounces of finely pulverised cochineal are to be put into fonr
or six quarts of rain or distilled water that has been previously boiled in a pewter kettle. These
are again boiled together for six minutes more, adding according to some practitioners two
drachms of pulverised crystals of Tartar. Next add eight scruples of Roman alum in powder;
and the whole is kept on the fire one minute longer. As soon as the gross powder has subsided
and the decoction has become clear it is to be carefully decanted into large cylindrical glasses,
covered over and kept undisturbed, till a fine powder is observed to have settled at the bottom.
The liquor is then poured off from this powder which is to be gradually dried; and from the
liquor, which is still much coloured, the rest of the colouring substance may be separated by
means of the solution of tin, when a carmine little inferior to the former will be obtained.
Crocus Martis is obtained in different ways, but always with a solution of iron to be afterwards
precipitated. It may be made by calcining the mars yellow, in the same manner as the burnt-
terra di Sienna is procured from the raw mineral of that name : it is then dearer than that usually
sold in the shops, but it is lighter, more transparent, and more pleasant to use. This colour is
easy to work with, and unites perfectly with all others. From all martial ochres a red more or
less deep, may be obtained, by exposing them to the action of fire : but the quality is greatly
inferior to that obtained from martial vitriol.
Minium or Red Lead is lead calcined until it acquires a red colour, by exposing it with a large
surface to the fire. It may also be made from litharge, which is a semi-vitrified oxyde of lead,
obtained by keeping a stream of air upon lead when in fusion, and generally procured in the
course of separating silver from lead ; but the minium in this way is not so good as when
obtained from lead in its metallic state. Red lead is very apt to turn black, both in water and
oil, and is therefore seldom used but for coarse works.
Vermilion or Cinnabar is a bright scarlet colour, procured by combining mercury with sulphur.
Cinnabar is found in a natural state in many parts of Europe; it is then compact and generally
of a colour resembling brick-dust: when it is reduced to powder it approaches somewhat to
carmine, being then called vermilion. The goodness of cinnabar may be known bv observing
the colour of the flame arising from it, when placed upon red hot ashes; if the flame be blue,
bordering upon violet, and no smell arise from it, the cinnabar is of a good quality. Artificial
Cinnabar is a mixture of mercury and sulphur sublimated by fire, and ought to be of a fine deep
red. This sort of cinnabar is often preferred to the natural. To procure the vermilion, grind
the cinnabar with water on a piece of porphyry, which diminishes the intensity of its colour and
produces a beautiful red. After this grinding dilute it in more water, and letting it stand for a
short time, pour off the water while it is still loaded with colour, by which means you will
separate the finer from the coarser parts of the vermilion. The water being again allowed to
settle completely the pure vermilion is obtained, and the coarse parts are again ground and
washed as before. To have the vermilion as pure as may be, you should grind it afterwards
upon porphyry, with child's water or brandy, and let it dry in the shade; to give it a lighter
tone you may mix with the liquid a little saffron. A very beautiful vermilion colour may be also
obtained by mixing powdered cochineal with burnt alum, and quenching them in rose water.
The colour brought from China is superior to any other, but it is apt to turn black.
Saturnine Red is prepared nearly in the same manner with minium or common red lead, of
which it is only a variety : and is afterwards washed repeatedly in large quantities of distilled
water,