Abstracts

p. 10-15


Texte intégral

Présentation,
by Georges Roque

p. 17

1Each of the contributions to this collective volume is introduced and replaced within its frame: Chevreul's principles and method, ancient and modem colour classifications, as well as art history during the nineteenth and early twenthieth century.

Michel-Eugène Chevreul, his life and works,
by Raoul Chevreul

p. 31

2The life of the great scientist is reviewed by his great great grandson.

About the exhibition «Il y a cent ans, Michel-Eugène Chevreul 1786-1889»,
by Bernard Bodo

p. 45

3This exhibition was presented in the Muséum national d’Histoire naturelle where Chevreul had worked for about 80 years. The aim was to recall the main contributions of this famous long living chemist in two fields of chemistry, by showing the chemical compounds he isolated and worked on, some apparatus from his laboratory and the original editions of his books and publications: in the Muséum he isolated, named and described most of the fatty acids, the cholesterol and gave the first scientific explanation of saponification. At the Manufacture des Gobelins, where he was Director of the dye workshop, he studied the contrast of colours and their classification. The celebration of his centenary in the new zoological Galeries of the Muséum in 1886 was also evocated.

Chevreul and Berthelot,
by Jean Jacques

p. 61

4Michel-Eugène Chevreul (1786-1889) and Marcelin Berthelot (1827-1907) are two outstanding figures of nineteenth-century French chemistry. Their relationship, as shown in this paper, was far from being cordial.

Chevreul and biological colours or a missed date,
by Jacques-Louis Binet

p. 65

5There is another way to examine the relationships between colour and chemistry, which can be called «biological colours»: the dyes that are necessary for microscopical biology. In spite of his chemical education, Chevreul missed this important direction of research, for historical reasons due to the development of cellular theory in France.

Chevreul at the Manufacture des Gobelins,
by Chantal Gastinel-Coural

p. 67

6This paper describes for the first time an important part of Chevreul's activities: his work as director of the dyeing department at the Gobelins. Many unpublished archive documents have been used to portray the different tasks Chevreul was confronted with: research, teaching, administration.

Chevreul's concern for method,
by Marika Blondel-Mégrelis

p. 81

7At first sight, Chevreul's concern for methodological problems seems strange, as a chemical method has been successful since Lavoisier. In fact, Chevreul's purpose was mainly epistemological: his concern were, as he himself said, «to realize the way mind proceeds in the discovery of the unknown». His distrust both of interpretation and of the concept of «fact» leads him to propose a new method, called «a posteriori experimental».

Chevreul's chemical researches on dyeing,
by Gérard Emptoz

p. 89

8Michel-Eugène Chevreul's research activities on dye chemistry were a major scientific contribution to the related industrial processes during the past century. As Director of the dyeing department of the Manufacture des Gobelins, Chevreul was in charge of supplying the tapestry works with all dyed textile materials. Their colours were required to satisfy all the artists' requirements. In order to introduce scientific acquirements in this technical field in which empirical recipes were the used, Chevreul built up a large programme of systematic testing from the 1830's to the 1860's. All parameters that could affect the natural dyes fixation on textile fibers were studied, as well as the colour stability under various conditions. Consequently, results from these studies were widely applied by textile industries.

About Chevreul's 1848 chemical researches on fragments of antique wall paintings,
by Bernard Guineau

p. 101

9In the nineteenth century, scientists like Chaptal, Davy, Chevreul, Berthelot, Dumas were consulted by historians and archaeologists on the chemical composition of ancient artworks. Most of these studies concerned antique jewels or metal implements alloys, but some of them were also devoted to Roman or Mediaeval wall paintings, since the excavations at Herculanum or Pompeïa had revealed the whole world over their antique treasures and had given rise to a keen interest in discovering painting materials or painting techniques used by the old masters.

10Still, art historians and archaeologists failed to agree about the painter's ancient techniques. On the one hand, the supporters of the «a secco» technique contended that an organic binding such as oil, wax or tempera had been used, while on the other hand, some thought it more likely that a simple and genuine «fresco» painting technique had been used. Since no solution seemed to appear, it is small wonder that the scientists' help was soon called upon; among them, Michel-Eugène Chevreul was regarded as a specialist of the colours science and as the pioneer of the chemistry of lipids.

11Chevreul published the results of his experiments on the Saint-Médard-des-Prés wall paintings about 150 years ago in the comptes-rendus of the French Académie des Inscriptions et Belles-lettres.

12We therefore reinvestigate here these results from a historical point of view with an attempt at comparing them with our own experiments.

Chevreul and photography. A revealing theme of both his scientific activity after 1847 and his place within the scientific world,
by Josette Fournier and Paul Fournier

p. 113

13Chevreul's interest in photography, between 1847 and 1873, arises from the advices and the help he gave to Abel Niepce de Saint-Victor (1805-1870): he refered, presented and commented on at the Académie des Sciences the numerous memoires of this officer, a relative of Nicéphore Niepce. The two chemists used uranium salts, and found, thanks to photography, there was a persisting «activity», at a distance, and in the dark. They therefore discovered radioactivity forty years before Becquerel. This shows an ignored continuity in the history of science, from dyeing chemistry to radioactivity, linked by photography.

Chevreul's theory of vision in the nineteenth-century context,
by John D. Mollon

p. 137

14Chevreul's views on vision were developed within his own private framework and throughout his life he remained isolated from the writings of the German physiologists who dominated visual science during the nineteenth-century. His ambitious colour order system was the first to offer a set of references that were both practical and permanent, but the system was not based on the three dimensions of visual experience, and the larger part of his «hemispheric construction» is redundant. The law of colour contrast adds little to the concepts of Gaspard Monge, Count Rumford and Claude-Antoine Prieur, but Chevreul introduced to a broad, international public a set of phenomena that hitherto had been hidden away in scientific journals; he extended the concept of contrast to other perceptual dimensions; and his colour system provided a framework for the French tradition in the study of acquired impairments of colour vision.

Parallel between some observations made by Chevreul and current knowledge of visual functioning,
by Françoise Viénot

p. 147

15Four visual phenomena described by Chevreul have been selected and explained in relation to recent knowledge of visual functioning. The two ways of judging Value are clarified. The physiological origin of contrast is assessed, together with a clear distinction between simultaneous contrast, successive contrast and rotative contrast. The several mechanisms of visual functioning related to the three phases of rotation of the complementary top are outlined. Objective indices are given for a good vision of printed plates.

Coloured shadows phenomenon within the law of contrast,
by Philippe Lanthony

p. 159

16Coloured shadows occur when some object is illuminated by 2 light sources of different colours, and of similar luminosities. The hues of the 2 shadows are always complementary. Historical recall: coloured shadows were at first considered as physical entities; their psycho-sensorial character was evidenced by Rumford and Goethe, and they were incorporated by Chevreul in the global concept of simultaneous colour contrast. Nevertheless, the mechanism of the coloured shadows is still not settled: the role of chromatic adaptation, of marginal colour contrast, of the so-called «white reference» and of the saturation are discussed.

Ergonomy and subjectivity,
by Victor Grillo

p. 167

17The importance of colour contrast and subjectivity in colour perception are evidenced by their constant use in our environment. The examples given and discussed arise from the author's own experience and participation as colourist to the ergonomy of several buildings.

NIMES, the new colour space,
by Daniel Tabary

p. 185

18The colour classification system invented by Chevreul as well as the chromatic circle he constructed are of first importance for the Manufacture des Gobelins and are still being used. But some of the dyed wool samples are now missing.

19In order to reconstitute and preserve Chevreul's heritage, an experimental software, called NIMES (Nuancier Informatique des Manufactures nationalES) is currently being tested.

From Chevreul to the new computing technologies in the field of colour,
by Jean-Paul Longavesne

p. 193

20This paper discusses Chevreul's colour classification system and shows how it can be adapted to instrument needs by using all the possibilities given by a micro-computer. The NIMES software constitutes an important tool for colour representation whose interest extends beyond the Manufacture des Gobelins.

Chevreul between classicism and romanticism,
by John Gage

p. 209

21Chevreul was the theorist of colour most consulted by nineteenth-century French artists, but the nature of their interest has often been misunderstood. Like his closest friend among painters, Horace Vernet, the chemist had his feet in both the Classic and Romantic camps: his emphasis on the simultaneous contrast of flat patches of colour, and the roots of his work in the decorative arts appealed to Classicists like Hersent and Ingres, as well as to Delacroix who, at the end of his career, turned to Chevreul for enlightenment when he was faced with the increasing problems of ceiling painting, in the Salle d'Apollon of the Louvre. Chevreul's recognition ot the power of chiaroscuro as the primary form of simultaneous contrast made his work of special interest to Seurat and the Neo-Impressionists.

Simultaneous contrast and the visual arts,
by François Molnar

p. 217

22Chevreul's book on simultaneous contrast was first published in 1839. Thirty years later, when Impressionists were faced with similar problems, they however didn't feel it necessary to turn to the great chemist's theory. The results of the rising science of chromatic perception (Helmholtz, Young, Mach) did not interest them either.

23Though the phenomenon of simultaneous contrast was known by painters for centuries, it had not been explicitly used before Seurat and Signac. But Delaunay is the first painter, at the beginning of this century, to have consciously used in his work all the creative possibilities of Chevreul's theory.

24Except in Albers' important work, the theory of Chevreul still doesn't have the place it should have, as one of the bases of an autonomous theory of visual arts.

Chevreul: Contrast and harmony in the art of gardening,
by Guy Lecerf

p. 233

25For Chevreul, the garden is a privileged place for colour experimentation. He desires to link art and science. He applies the a posteriori experimental method to it and develops a formal logic with it.

26Thanks to his tables – chromatic circles and boards of combinations of colours – the gardener should gain the standing of «jardiniste» at the same time engineer and artist. Chevreul obtains in France an agreement in principle: the treatises of mosaïculture adopt its harmonies of contrast. On the other hand, in England, it is the subject of controversies between belonging to the bedding system: the partisans of contrast clash with those of the harmonies of nuance. However, the importance that it grants to the syntactic relations, with the types of combinations of colours, the broader systems like the «coloris» and the «système des teintes plates», does of Chevreul one of the essential reference of the art of the gardens.

How painters received Chevreul's plates and ideas,
by Georges Roque

p. 247

27The interest Chevreul's theory of colour contrast changes from one generation to another. That's why it seemed interesting to point out some of the interpretations painters gave to the law of simultaneous contrast. This paper emphazises first the visual impact that colour plates of Chevreul’s famous book (The Principles of Harmony and Contrast of Colours) had on some artists and proposes that painters were more interested in looking at the plates than in reading the book, which could have played a role in their misunderstanding of the law of contrast.

28At the beginning of abstract art some other painters looked at Chevreul from the point of view of the «colour syntax», or «grammar of colour»: the theory of simultaneous contrast provides a scheme for pure abstract colour relations.

29At the same time (around 1912) the words «simultaneous contrast» and «simultaneity» also played an important role into the development of what has been called the «aesthetics of simultaneity».


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