© 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

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.
Comparison of mineral pigments and
synthetic pigments under the

The natural mineral Azurite and the
synthetic pigment
Cobalt Blue (invented in
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

Lapis lazuli (natural ultramarine)
French Ultramarine (invented
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: