© 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

The natural mineral Azurite and the synthetic
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
Mineral Pigments under the Microscope
Cadmium red 40x
Page 3
The images on this page are examples from
the two volume book:
"Renaissance Mysteries, Vol. I: Natural
Colour and Volume II: Proportion and

For further information go to: