Red Lead, Minium, Or Saturnine Red, is an antient pigment, by some old writers confounded with cinnabar, and called Sinoper or Synoper, is a deutoxide of lead, prepared by subjecting massicot to the heat of a furnace with an expanded surface and free accession of air. It is of a scarlet colour and fine hue, warmer than common vermilion; bright, but not so vivid as the bi-iodide of mercury, though it has the body and opacity of both these pigments, and has been confounded, even in name, with vermilion, with which it was formerly customary to mix it. When pure and alone, light does not affect its colour; but white lead, or any oxide or preparation of that metal mixed with it, soon deprives it of colour, as acids do also; and impure air will blacken and ultimately metallize it.

On account of its extreme fugitiveness when mixed with white lead, it cannot be used in tints; but employed, unmixed with other pigments, in simple varnish or oil not rendered drying by any metallic oxide, it may, under favourable circumstances, stand a long time; hence red lead has had a variable character for durability. It is in itself, however, an excellent dryer in oil, and has in this view been employed with other pigments; but, as regards colour, it cannot be mixed safely with any other pigments than the ochres, earths, and blacks in general: when employed in water, the reds of lead, iodine, and mercury are warmed and brightened in colour by the addition of gum; this it does mechanically by allowing the darker particles to subside.