© Michael Price Inc.
| A Comparison of Mineral Pigments and Modern Synthetic Pigments I would like to thank Chris McGlinchey, scientific conservator at the MoMA in New York for the following microscopic images. This is part of an on-going project to monitor the performance of my preparation protocols for natural and mineral pigments. Artists who are interested in the luminosity of the colours of the Old Masters will find the answers to their questions lie not so much with the recipes for mysterious painting mediums, but more simply with the pigment particle sizes of natural and mineral pigments compared to the particle sizes of modern synthetic pigments i.e. pigments developed since the beginning of the 18th century. This page presents an introduction into the difference between natural and mineral pigments, and synthetic pigments. The main difference is the pigment particle size. With the natural and mineral pigments, the pigment particle varies between about 10µm (microns) to about 80µm (1µm = 1,000th of a millimetre). Fine sand is about 100µm. Synthetic pigments vary in size, but are generally below 1µm. This difference affects the luminosity of the pigments and therefore the paint layers. With the larger pigment particle sizes, more light passes through the pigments and is reflected from the white ground of the painting resulting in that glow of the paintings by Renaissance Masters. For details see my paper under Publications: "A Renaissance of Color". |
| Comparison of mineral pigments and synthetic pigments under the microscope. The natural mineral Azurite and the synthetic pigment Cobalt Blue (invented in 1806). Comment: Two to three layers of azurite with a pigment particle size between 30µm to 40µm in Strasbourg turpentine and a few drops of walnut oil will produce a similar hue to cobalt blue. However, the chromatic intensity and luminosity of the azurite is superior. The cobalt blue has greater covering power. Lapis lazuli (natural ultramarine) and French Ultramarine (invented 1827). Comment: French ultramarine is an extremely fine powder - it is shown here with a 40x magnification. This pigment replaced the semi-precious stone lapis lazuli. Athough natural and synthetic ultramarine are chemically the same, their hues are remarkably different. Cinnabar and Cadmium Red Medium (invented about 1910). Comment: Although cadmium red replaced cinnabar on the artist's palette, there is no comparison between hue, saturation and chromatic intensity of the two colours. |
Cinnabar 40x
Azurite 16x
Lapis lazuli 16x
Azurite 40x
Cobalt blue 40x
French Ultramarine 40x
Cinnabar 16x
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