The substance given the name the "Red King" by alchemists may be none other than the pigment vermilion.
Vermilion was important in art from early times until the mid-20th century - known as a reliable pigment - it was ground to ensure that it had not been mixed with red lead or brick. One hazard of vermilion is that its constituent ions can reshuffle from their usual positions to new locations in a form the black form of mercury sulphide known as metacinnabar. This absorbs red light as well as blue and green. And so, to prevent the vermilion turning black on exposure to light, it was covered with a protective coat of wax and oil, which was then heated and polished with linen cloths and waxed cords.
Preparation of vermilion from mercury and sulphur was worked out in detail by medieval alchemists as it was considered by some adepts to be the preliminary stage to the Philosophers Stone which was capable of converting base metals into gold. Knowledge of the manufacture of vermilion was derived from the writings of alchemists. The Benedictine monk Theophilus (1070-1125) in his technical handbook De diversis artibus "On Divers Arts" (c. 1122), provide a description of an alchemical synthesis in which sulphur and mercury are placed in a sealed pot and buried in "blazing coals". Theophilus commented that, "you hear a crashing noise inside, as the mercury unites with the blazing sulphur." The general result of this process was a lump of solid red vermilion. Cennino added that, "If you grind it every day for twenty years, the colour would still become finer and more handsome." By the 17th century Holland had became the principal centre of vermilion manufacture in Europe. The Dutch combined mercury and sulphur to form metacinnabar. The metacinnabar was then pulverized and sublimated by strong heating, so as to convert it into red vermilion. The German chemist Gottfried Schulz subsequently developed this method further by converting metacinnabar to red vermilion by heating it in a solution of ammonium or potassium sulphide, resulting in a fine powder with uniform grain size and an orange-red colour.
The pigment was used by Johannes Vermeer (1632-1675):
- Mixed with lead white to produce flesh tints.
- For the red gown in The Glass of Wine and in the Girl with a Wineglass, and for the red plumed hat worn by The Girl with a Red Hat - was then glazed with madder lake.
- To paint the oriental carpets which appear on the tables in many of his interiors, which were also glazed.
George Field described vermilion as:
Field's Chromatography or Treatise on Colours and Pigments as Used by Artists
"Deep or pale, when well made and pure is of strict permanence, not sensibly affected by light, time, or foul air; and eligible either in water, oil, or fresco. For an enamel colour it is unsuited, being dissipated at a red heat, a test that detects the presence of any non-volatile adulterant. The best vermilion is a powerful vivid colour, higher in tone than all reds, except the scarlet iodide of mercury. With this it should not be compounded, but with other pigments it may safely be used in admixture, as far as its own colour is concerned. Of great body, weight, and opacity, it is a somewhat slow drier; and does not retain that brilliancy when dry, which is peculiar to it while wet. A want of transparency, and not drying well, prevent its being so generally employed as would be desirable. Pictures should seem to be painted with colour, not with pigment, the material being lost amid the hues, tints, and shades; but with such compounds as vermilion, the art of concealing art becomes difficult indeed. The pigment is apt to predominate over the colour, and the painting to look mechanical rather than natural: particles are apparent where hues alone should be seen, and all sense of reality is destroyed. For these reasons, vermilion is a dangerous pigment in unskilled hands, needing an intimate acquaintance with its physical properties. The extreme weight or specific gravity of the red renders it liable to sink and separate when compounded with other colours; hence the heavier those mixed with it the better. Its almost equal opacity, too, and habit of washing up, militate against its use by young painters. With experience, however, and due care, this is a serviceable colour; yielding with white most delicate flesh tints, and in minute proportion with cobalt or French blue and white, tender aërial grays.
"Being cheaper than formerly, vermilion is not so much adulterated as it once was; although, even now, brickdust, orpiment, &c. sometimes sophisticate it. The knavish practices to which the pigment has been subjected, have acquired it an ill-fame both with authors and artists. Vermilion has been charged with fading in the light, and with being blackened by impure air; but it was the custom to crimson the colour by means of lake, or tone it to a scarlet hue by red lead. With pigments as with persons, evil communications corrupt good manners - a motto that might be written with advantage on every palette."