For further details go to: http://conference.collegeart.org/2007/

Michael Price chaired the session titled:
"The Contemporary Relevance of the Renaissance Palette"

on Saturday, February 17, 9:30 AM–12:00 PM
Regent Parlor, 2nd Floor, Hilton New York

SESSION ABSTRACTS

Session Abstract: The Contemporary Relevance of the Renaissance Palette.

Contemporary artists are showing increased interest in the use of natural and mineral pigments such as lapis lazuli, azurite, malachite,
cinnabar, orpiment, realgar, natural root madders, indigo and cochineal after about 200 years of modern synthetic pigments. This session is
interdisciplinary and will evaluate the progress made by artists, conservators, restorers and pigment manufacturers in understanding the
properties of these pigments and paint layer performance in a variety of binding mediums. Much of the literature about the preparation and
application of the pigments in tempera and drying oils is confusing and contradictory. In addition, there is no information available about the
performance of these pigments in modern synthetic binding mediums.

Speakers will address the following:
a. the properties and preparation protocols of natural and mineral pigments, their advantages and disadvantages
b. historical natural binding mediums will be compared to modern synthetic developments with regards to performance and longevity
c. there will be a special focus on the blue pigment azurite and the preparation of red pigments.

Finally, the use of the "historical" pigments will be put into context with regards to the developments over the past two hundred years. In
addition, the importance of the painting support and ground, both traditional and modern, will be considered.

1.
The Use of Traditional Pigments in Conjunction with Contemporary Binding Media and Techniques
Michael Skalka, National Gallery of Art, Conservation Division

Contemporary artists employing natural and mineral pigments have overwritten old methods of preparation used by Renaissance artists.
With a variety of traditional and new synthetic binders available today, the proclivity to experiment with pigments in new media has
become an avenue for expressing an artist’s intent and expanding the range and behavior of traditional colorants.

While some of the new techniques appear to be intriguing, are natural and mineral pigments worth the expense and effort to prepare? This
paper will examine a selection of traditional natural and mineral pigments using a variety of binder and application techniques to describe and
catalogue the physical properties of these colorants. Discussion will focus on the degree of difficulty in achieving a desired technique, safe
handling of the materials and physical compatibility of pigments with their binders, pigments and supports, durability, and appearance of the
materials examined. Where applicable, visible light spectral comparisons will be made to demonstrate how various binding media saturate
and develop colors to maximize or retard their potential. When relevant, modern synthetics will be compared with traditional natural and
mineral pigments to illustrate how their properties surpass or fall short of the unique characteristics of traditional colorants.

Physical descriptions of all of the materials used, the techniques employed and images to illustrate the results of experiments with pigments
and binding media will be presented. The presentation will address when relevant the documented shortcomings of a variety of traditional
pigments to emphasize instances where shortened longevity of colorants is significant.

2.
The Effect of Different Binding Media on the Colour of Azurite Paints during Ageing
Shuya Wei, Vienna University of Technology

During the Middle Ages and Renaissance, Azurite was the most important blue pigment in European painting. It has a molecular formula
2CuCO3•Cu(OH)2, chemically similar to the green pigment malachite CuCO3•Cu(OH) 2. Although under ordinary conditions it is stable,
there is evidence in the literature that it may become green in tempera paint as a result of conversion (on hydration) to the less stable form
malachite. Tempera was traditionally created by hand-grinding dry powdered pigments into egg yolk, sometimes with other materials such
as honey, water, casein and a variety of plant gums. After the introduction of oil paint in the Late Middle Ages, tempera continued to be
used as the under painting with transparent oil glazes.

According to the literature, a variety of binding media were used to make azurite paints. However if the blue colours are prepared using old
recipes, it is difficult to obtain the desired colour. In addition, after a short period, the colour of the paint has changed. But one can see from
Flemish paintings that the azurite blue colour is in excellent condition even after hundreds of years. The question is why the blue has not
been affected so much in the ageing of binding media in the old master paintings? Were there other materials used in these paintings not
mentioned in the recipes?

In order to better understand the master old paintings and also for conservation purposes, different binding media have been applied to make
azurite test paint samples, including casein, egg, linseed oil, walnut oil, Strasbourg turpentine and mixtures of these (samples have been
prepared by Michael Price). The samples have been subjected to artificially accelerated ageing. The colour change will be documented by
using digital camera and colour meter in different ageing intervals to see which recipe is the best to keep the desired blue colour. GC-MS
will be applied to measure the chemical change of the binding media used. The reason for the different lightfastness of the blue paint samples
could be elucidated by combining the optical and the analytical results during ageing. This will not only provide information for interpreting
the old master paintings, but also provide scientific support for contemporary artists and conservators wishing to imitate the blue colour and
obtain a good lightfastness.

3.
The Preparation of Red Pigments, Cinnabar, Purple, Carmine and Madder Lake compared with the New Products
Dr. Georg Kremer, Kremer Pigments

As producer of artist’s pigments including a large selection of natural and mineral pigments, finding the best source for the raw material is of
the utmost importance. One of the main sources for red pigments historically was the mineral cinnabar. It is the principal ore of the metal
mercury. The crushed ground ore served directly as a pigment for centuries. The historic source for cinnabar was the famous Almaden
mines in Spain which are still the world's most important source of mercury. Cinnabar is fairly widely distributed in nature and sources are
known in England, Spain, Italy, China, Japan, California, Mexico and Peru. Cinnabar is the common red crystalline form of mercuric sulfide.
Vermilion is the standard name in England and the United States given to the red artists' pigment based on artificially made mercuric sulfide.
Artificial cinnabar was manufactured very early on. Geber (Jabir), the eigth- to ninth-century Arabic alchemist mentions a red compound
formed by the union of sulfur and mercury. The pigment has been known in China since prehistoric times and it has long been held in high
esteem there.

The artificial dry-process vermilion does not differ from the natural mineral. Artificial vermilion, produced by the wet-process, contains
very finely divided and homogeneous particles. The mineral cinnabar is coarsely cristalline and has a bluish, carmine red color. When it is
finely ground, the color approaches a reddish orange.

Other important reds from plant and insect origin, including the root madders and cochineal, will be compared with some of the modern
alternatives. Pigment examples including earthy reds, such as red ochres and red jasper to pinks from red coral all from my New York
outlet, will provide an additional insight into the range of red pigments now available to the artist.

Finally, there are variety of problems one faces when collecting some of the raw materials to produce the pigments. Here the expense can
be formidable, for instance with Tyrean purple, imperial purple. The royal red of antiquity is named after Purpura Lapillus, the shellfish
which excretes the purple dye, also called Tyrean dye. Traditionally adorning the robes of emperors, kings and chief magistrates, 1 gram of
this dye is made from the secretion of 10.000 of these large sea snails.

4.
The Myth of the Secret Juice of the Flemish Masters
Michael Price, Artist

The luminous colour of the Flemish masters of 15th and 16th century Europe has such a fascinating physical quality that generations of artists
have tried to imitate the so called 'enamel-like' finish. A wide-spread myth has developed that this surface quality has something to do with
the use of a secret painting medium, or even an emulsion. However, luminous colour with natural and mineral pigments, such as lapis lazuli,
azurite, malachite, cinnabar, natural madders and natural ochres is achieved through a combination of factors. These include pigment purity,
pigment particle size, refractive index of the pigment combined with the nature of the painting medium. Binding mediums have to vary
according to the refractive index of the pigment and the number of superimposed paint layers to arrive at the required depth of colour. On
the purely practical level, there is no one traditional binding medium that functions optimally for all of these variable parameters.

The prerequisite for colour luminosity is pigment purity. This is achieved through pigment levigation in a proteinaceous solution. For most
pigments, I have found that casein functions the best since numerous impurities, especially cuprite in azurite and malachite readily floats out
of the solution. Hide glues are less effective. A weak egg yolk solution may be used with certain pigments. Impurities such as cuprite or
pyrite will have disastrous effects in paint layers. For instance, if there is more than 5% pyrite in natural ultramarine extracted from lapis
lazuli, the blue will turn grey in most binding mediums within 5 years. The avoidance of the discoloration of paint layers will be presented in
detail.

The choice of binding medium relates more to the physical properties of the pigments rather than the personal preference of the artist.
Analysis of binding mediums published by conservation departments often reveal considerable differences throughout a painting without any
further comments as to why. Based on 16 years of practical experience painting exclusively with "historical" pigments together with tests
carried out at my request by various scientific institutions, the following binding mediums are discussed relative to what is optimal for each
pigment:
a. Rabbit-skin glue, casein and egg tempera
b. Strasbourg and Venetian turpentines fused with spirits of turpentine
c. Cold-pressed refined walnut and linseed oil, co-polymerized and heat bodied oils
d. Sandarac, mastic and amber varnishes.


The College Art Association supports all practitioners and interpreters of visual art and culture, including artists and scholars, who join together to cultivate
the ongoing understanding of art as a fundamental form of human expression. Representing its members' professional needs, CAA is committed to the highest
professional and ethical standards of scholarship, creativity, connoisseurship, criticism, and teaching.
Crystals and Minerals including lapis lazuli, azurite, cinnabar, orpiment, realgar and malachite
College Art Association Conference 2007