Minium (Red Lead) Oil Paint

Minium (Red Lead) is a deep orange-red color. Minium, which is red lead or lead tetroxide, is an oxidation product of lead. Lead pigments have been made artificially since antiquity, although health concerns of lead poisoning have greatly diminished its role in paint today.

We provide the following notes about Minium (Red Lead) because specific issues about historical pigment have been noted in conservation literature. We continue to test this color under different conditions to determine if observations noted in conservation studies are also valid for Rublev Colours Minium (Red Lead) Artist Oil since it differs physically from historical minium.

According to some studies, minium is liable to discolor in the presence of hydrogen sulfide, which is present in air pollution in some developing nations. It may also react when mixed with sulfide pigments, such as cadmium and vermilion. Conservation literature states that red lead has been known to darken under certain conditions, such as when used with pigments containing free sulfur. This was the case for improperly made cadmium and vermilion pigments, but since manufacturing processes have improved during the past century, this has not been observed with modern sulfide pigments.

In oil paint, it is relatively permanent. However, some studies have noted that when mixed with white lead, it tends to fade rather than darken. In conservation literature, paint layers containing red lead and white lead exposed to high humidity were found to lighten or fade. We have not observed this in our testing to date, but we are testing this further.

When we first made minium in oil paint, we did not use any additives, so its shelf life was about one year until it hardened in the tube. This chemical reaction of red lead in oil was well-known for several centuries. Unlike any other oil paint manufacturer, we do not use additives in Rublev Colours Artist Oils. However, to extend their shelf life, we decided to use the additive aluminum stearate in this formulation to delay the hardening of red lead during storage. This dramatically extended the life of the paint during storage, and now the shelf life exceeds one year.

Composition and Permanence

For a detailed explanation of the terms in the table above, please visit Composition and Permanence.

Notes

Some separation of pigment and oil may occur in Rublev Colours Artist Oils and is a natural process when no wax or stabilizers are added to paint to prevent this from occurring.

All images of color swatches on this website are only approximations of the actual color of the oil paint. We have carefully matched the color in these pictures on calibrated color monitors to the actual color. However, your results may vary because of the wide variance in color monitors.

Color Swatch Note: The color swatch was created with a thick application (left side) of color and a tint (right side) made with equal parts of color and titanium white and applied on acrylic primed cotton canvas.

Drawdown Note: The image of the "drawdown" contains a pre-mixed paint film of 6 mils (0.006 inches) thickness applied to a standard test card to examine color consistency, opacity, and other qualities. The drawdowns show the color's full strength (mass tone) on the left and mixed in a 1:2 ratio with titanium white on the right. The bottom area of the drawdowns is scraped to show undertones.