Strictly speaking a scientific revolution cannot have either a starting point or and end point. It is always part of an ongoing process. However, two events provide milestone contributions to the scientific revolution in the understanding of visual perception that took place in the 18th and 19th centuries. The first was a lecture given by Gaspard Monge in 1789 . The second, the publication of a book by Hermann von Helmholtz in 1867. In between these two dates, various other scientists made key contributions to the science of visual perception. Three worth special mention were Johann Wolfgang von Goethe, Michel Eugène Chevreul and James Clerk Maxwell.
What these five men helped the scientific community to make crystal clear is that colour is not a property of surfaces in the external world, but a construction of the eye and the brain. The word “colour” only has meaning as an experience. A corollary of this realisation is that it is meaningless to describe the patterns of light of variable intensity and wavelength that enter the eyes as having colour. Whatever their wavelength, they are still only light.
Nor was it long before the scientists were forced to the conclusion that it is not only colour that is made in the head, but all conscious visual experience. No scientific revolution could have been more radical in its implications. Everyone, including artists, were confronted with the fact that there is a gulf between the “measurable reality”, which had previously been assumed, and the “experienced reality”, to which they now had to reconcile themselves.
Artists have to question their rules
No wonder artists took note. How exciting it must have been to partake of the unsuspected visual banquet that they now found to be available to them in every moment of their everyday lives. But this was not all. I was not just that they found themselves looking differently. In addition, they were forced to question the rules that underpinned the academic method that they had all been brought up on. At the very least these would need to be revised. Quite possibly they would have to be jettisoned.
In short, new rules, new ways of looking and new ways of doing were clearly required. It was the growing acceptance of these realisationst that played a significant part in galvanising the young Impressionists and their immediate successors into the new conceptual frameworks that provided the impetus for the Modernist Revolution in Painting. Nothing in painting would ever be quite the same again.
Gaspard Monge (1746 – 1818)
Monge was a highly reputed French mathematician. He invented descriptive geometry (the mathematical basis of technical drawing) and has been described as the “father of differential geometry.” However much more important for this Post in the section on Painting, he gave a lecture on color vision to the Academy of Sciences in April 1789. In this he demonstrated the constructive nature of colour perception. A key part of his argument was a demonstration of colour constancy that showed the importance of whole-field relativities in creating what we see. His theorising about how the eye/brain enabled it proved to be almost two hundred years ahead of its time (It was not until 1977 that Edwin Land published similar ideas in the Scientific American that they resurfaced into the public domain. Land’s article was called “The Retinex Theory of Color Vision”).
Johann Wolfgang von Goethe (1749 – 1832)
In my experience people tend to be surprised when I mention that Goethe , the famous German playwright and poet, was also a scientist. It is said that, in his own view, the book recording his lifelong interest in visual phenomena was as important as his literary achievements. Amongst the observations he recorded were ones of after-images and induced colour. He was by no means the first to observe either (For example, Monge demonstrated induced colour) but, probably because of his reputation as , a poet and playwright, it was often his ideas that were picked up by the artistic community. Also, his proposals concerning the relation between colour and emotion were to prove extremely influential with artists, including Gauguin, Kandinsky and many, many more.
Michel Eugène Chevreul (1786 – 1889)
Chevreul was a chemist employed by the famous Gobbelin tapestry producing factory. His expertise was needed because, as a consequence of the Industrial Revolution, new dyes were being created at a unprecedented rate. His job was to test the new products for permanence (particularly light fastness) and for compatibility with other dyes and materials used by artists. As a sideline he got interested in visual perception. It is to him we owe the law of simultaneous colour contrast, which states that, when any two colours are juxtaposed, the difference between them is exaggerated by the eye/brain. The fact that the law applies when black and white are juxtaposed provides early evidence that the eye/brain treats them both as colours. However it was not until the 1970s, when Semir Zeki found colour coded cells in are V4 of the visual cortex, that this hypothesis was confirmed.
James Clerk Maxwell (1831 – 1879)
Clerk Maxwell has been described as the “Father of modern physics“. His most notable achievement was to formulate the now classical theory of electromagnetic radiation, bringing together for the first time electricity, magnetism and light as manifestations of the same phenomenon. His equations for electromagnetism have been called the “second great unification in Physics” (the first having been produced by Isaac Newton).
Maxwell’s importance for artists stemmed from his work on the relationship between light and colour. This provided one of the sources of Georges Seurat’s ideas about colour mixing. Maxwell’s experiments showed that optical mixtures of pigment colours obeyed the laws of additive mixtures, as opposed to the subtractive ones that govern paint mixtures on the palette. This keyed Seurat into his pointillist theory which is based on the idea that small closely packed dots of colour will mix additively, when viewed at a distance from which the blend optically. This was the theoretical basis of Seurat’s claim that Pointillism was a method of “painting with light“.
Hermann von Helmholtz (1821-1894)
Helmholtz was a polymath who made important contributions to several fields of science. In physics, he is celebrated for his theories on the conservation of energy, work in electrodynamics and thermodynamics. As a philosopher, he is known for his philosophy of science. More importantly from the perspective of this Post, he has also been described as “The father of the Psychology of Perception”. His landmark book on this subject, “The Handbook of Physiological Optics”, was published 1867 at the time the young Impressionist were meeting in the café Guerbois. In it he made his synthesis of the new developments in the study of visual perception. On the basis of this, he developed his theory of cognitive inference, which proposed that human visual capacities could not be explained on the basis of visual input alone: There had to be another factor. Helmholtz argued that this could only be the use of information stored in memory. In other words, he claimed that visual perception is a constructive process. In doing so he gave support to the idea that visual experience is made in the head.
Summary of the influence on painting of the scientific revolution
All the five scientist featured above played important roles in the scientific revolution that gathered momentum in the nineteenth century. Three of them (Monge, Clerk Maxwell and Helmholtz) had such an important place in it that they have been described as “Fathers” of their main subjects “Differential geometry”, “Visual Perception” and “Modern Physics” respectively. In addition all five of these remarkable men played important role in helping artists to realise that there is a significant difference between “measured reality” and “experienced reality“. In doing so they provided what lay well have been vital grist to the mill of the Modernist Revolution in Painting. Very possibly, without the scientific revolution in which they played such important roles, it would never have taken place.