The purpose of this Post is to provide a link to Chapter 10“Illusory pictorial space and light”, from my book, “Painting with Light and Colour”. This provides a simplified explanation of the science behind the ideas developed in earlier chapters concerning ways of creating and/or enhancing effects of illusory pictorial space by means of using mixtures containing small proportions of complementary colours. In the process it explains why the same method can be used to create harmony in paintings. It also explains why colour repetition has the potential, not only to produce visual discord, but also to generate optical excitements.
Examples of painting space and creating harmony with colour
Paul Cézanne: Still life, provides and example of how making a painting that fits into the rules of Professor Bouhusz-Szyszko creates a sense of space, light and harmony.
Pierre Bonnard: Landscape, provides a second example of how making a painting that fits into the rules of Professor Bouhusz-Szyszko creates a sense of space, light and harmony.
Examples of repeated colours without mixtures of complementaries
Francis Bacon : On of his Pope paintings, in which repeated colours, whether intentionally or not, enhance shock value
Jackson Pollock : Echo No 23 (detail) -The influential critic Clement Greenberg admired Pollock for creating a “space within the picture surface”.
Victor Vassarely : Op Art – used lstrong cognitive cues and many repeating colours to create a powerful visual impact.
Other chapters from “Painting with Light and Colour”:
In many places in my books, I acknowledge the importance of the role of colleagues from University of Stirling in the development of the new science-based ideas put forward in them. In particular I mention cooperations with scientists from various departments who later were to join me in the University of Stirling Vision Group. The most important of these were:
Alistair Watson (Physics, psychology and computer imagery).
Lindsay Wilson* (at the time working on aspects of visual perception).
Also, although Peter Brophy* did not join our group, he was an ever-available and important source of information on the biochemistry of the brain.
The founding of the Vision Group.
It was in the Autumn of 1984 that Alistair, Leslie and I took the first steps in the setting up of the University of Stirling Vision Group, which was to have many meetings attended by the above named colleagues and other members of the various interested Departments. Its starting point was a package of ideas developed by Alistair and myself, and two core algorithms based on them, produced by Alistair. These were:
A “colour constancy algorithm“, capable of modelling both spatial and temporal colour constancy, which was inspired by our interpretation of how this phenomenon is achieved by human eye/brain systems. As a preliminary step to achieving this main objective, the algorithm has to pick off the information about surface-reflection. Since it was obvious that the reflected-light contained information, we speculated upon how it might be used by the eye/brain. Due to my interest in picture perception, we focused on its potential for computing surface-form, in front/behind relations, and the wavelength composition of ambient illumination.**
A “classification/recognition algorithm”, based on our interpretation of how human eye/brain systems achieves their primary task of enabling recognition.***
We could not help being excited by the early tests of these algorithms and the speculations concerning their potential. In our enthusiasm to push matters further, Alistair suggested we should seek the help of other researchers, particularly ones with expertise in:
Mathematics and computing.
Visual perception with special reference of visual memory.
It was at this juncture that, having decided on a name for what we were hoping would become a collaborative group, we contacted Leslie Smith for his mathematical and computing skills. But this was only a start. Once Leslie was on board, we approached Bill Phillips, whose long standing interest in visual memory had led him to take the plunge into the recently emerging domain of neural networks and learning algorithms. After many Vision Group meetings, much sharing of ideas, many hours spent working on implementations of algorithms, and the writing of a number of working papers, we decided to submit a suite of five grant applications to the Science and Engineering Research Council, who had let it be known that they were looking for groups of researchers working on the use of computers to model the functional principles of neural system. The stated aim of the SERC was to set up a small number of “Centres of Excellence” in this domain. Not only were two of our grant applications accepted (one submitted by Bill Phillips and one submitted by Leslie Smith), but also our university was encouraged to create a brand new Centre for Cognitive and Computational Neuroscience . This empire absorbed the University of Stirling Vision Group which ceased to have an independent existence. Its coming into existence also coincided with my departure from Stirling on my way to founding my Painting School of Montmiral, where I intended to put theory into practice both in my own work and in my teaching. I also had hopes of confirming and, with any luck, extending the theory.
What we see is not light, but experiences created by neural networks within the eye and the brain (what I often refer to as “eye/brain systems”). Although it is true that the visual world that we know could not happen in the absence of the patterns of light that enter our eyes, it is only made manifest to us as a result of what is going on inside our heads. This Post provides a link to Chapter 9 of my book “Painting with Light and Colour”, which describes two demonstrations that show just how great can be the difference between an image predicted on the basis of readings from a light meter and the one we actually experience.
Edwin Land’s demonstrations
The demonstrations have a personal importance because they played a key role in the story of my quest to explain the paradox inherent in the dogmas of Marian Bohusz-Szyszko(explained in Chapter 2). They were devised by Edwin Land, the famous inventor, as a part of his investigation of the phenomenon of “colour constancy”.
For another relevant source of information on Land’s demonstration please consult “Land’s colour constancy demonstration”, an edited version of a chapter from my book “What Scientists can Learn from Artists”. You might also want to read the original article in “Scientific American, December 1977”. In this Land explained what he described as his “Retinex theory of colour vision”.
The multicoloured display used by Land as the cover for his 1977 article in the “Scientific American”
.
Other chapters from “Painting with Light and Colour”:
The main purpose of this Post is to explain what I mean by “Seurat’s new idea”. Most people would probably leap to the conclusion that I am referring to the “Pointillist method” that he developed, and for which he is justly renowned. But the method was never the main idea, which was to “paint with light” (as opposed to merely “painting light”). No previous artist had attempted to do this.
At least since the Italian Renaissance, the artistic community had been particularly interested in depicting effects of natural or artificial light on the appearance of objects and scenes. They made impressive progress by conceiving matters in terms of whole-field lightness relations (chiaroscuro). Seurat’s new idea opened up the unexplored possibility of introducing the dimension of colour into the mix. In doing so, whether directly or indirectly, he was responsible for opening the way for the possibility of adding a new dimension to the experience provided by representations of the effects of light in paintings.
In itself, this step could justifiably be described as a “quantum leap”, but as it turned out the influence of Seurat’s new idea was to have other far reaching implications. In time it would also lay the foundations for enhancing, not only effects of “illusory pictorial space” but also the sense of both “surface” and “surfacelessness” in paintings.
But even this was not all, for another side-effect of Seurat’s new idea was its contribution to the explosion of colourfulness in paintings. This had been kick started by the discovery by scientists that colour is not a property of surfaces in the external world, but a creation of eye/brain systems. In the wake of this mind blowing reality, earlier Modernist artists were already using brighter colours and juxtaposing complementary pairs, but two requirements of the Pointillist method pushed matters significantly further. These were:
The systematic use of juxtaposed complementary colour pairs, within the optically mixed arrays of tiny dots that characterise Pointillism.
The need to conceive of colour mixing in terms of a colour circle with many more segments than the six segment one (consisting of three primaries and their three complementaries) favoured by the Impressionists. Seurat’s idea meant that he had to represent as many parts of the visible spectrum as possible. To do this he needed to make use of the widest range of the most fully saturated pigment colours available.
Between them these innovations had the effect of hugely increasing the range and subtlety of both colours and colour combinations to be found in paintings produced after 1886, the year that Seurat first exhibited “La Grande Jatte”, his game-changing painting.
For more details click on the link below to Chapter 8 of my book “Painting with Light and Colour”. For those who have not read the previous four chapters, the next section provides a short resume of them (links to the chapters themselves can be found at the bottom of this page).
Short resume of previous chapters
Chapter 4: Describes the Renaissance approach to painting light, which centred on local and whole-field lightness relations with particular reference to finding the darkest and lightest regions in the scene (chiaroscuro) and gradations of lightness across surfaces. In this scheme of things the depiction of shadows was a matter of painting “what you see”, which seemed reasonable enough, but brought with it all sorts of unsuspected problems.
Chapter 5: Focuses on the scientific revolution in the understanding of light and colour that had its origins in the work of Isaac Newton and the insights of the numerous scientists who realised that all sensory experiences including those that relate to colour and effects of light are made in the head. Newton clarified the physical nature of light. The perceptual scientists introduced concepts like the“three primaries”, “induced colour”, “complementary colours” and “colour/lightness contrast effects”.
Chapter 6 : Shows that the Impressionists had an agenda which included the idea of emphasising the reality of the picture surface and playing off the ephemeral and the permanent aspects of appearance.
Chapter 7: Uses photographs to elucidate the meaning of the words “opaque”, “translucent”, “glossy” and “matt”. Particular attention is given to effects on appearances of interreflections and viewing angles.
The diagrammatic origin of Seurat’s new idea
As it does not appear in Chapter 8, but earlier in the book, I am including in this Post the diagram from a physics book that kick started Seurat’s new idea. It was from this that he learnt that the white daylight light that strikes a surface interacts with it in one of two ways:
One part enters the surface and is scattered around inside, before being scattered back out again. While inside, some wavelengths are absorbed. The remainder are scattered-back-out again to produce the limited wavelength combinations that give us “body colour”.
The remainder never enters the surface, but is reflected back directly from it (as from a mirror), such that it leaves it without changing its wavelength composition to produce “reflected light”.
The component that interested Seurat is the “reflected light”. By combining his understanding of this with the discoveries of perceptual scientists mentioned above, Seurat believed that he could represent it in paintings by means of mosaics of tiny dots containing juxtapositions of complementary, or near-complementary, pairs.
The diagram that seeded Seurat’s new idea. It is the reflected back “white” light that informs the eye/brain about surface-solidity, surface-form, in front/behind relations and ambient illumination.
Posts relating to other chapters from “Painting with Light and Colour”:
The purpose of this Post is to provide the link below to “The perception of surface”, Chapter 7 of my book “Painting with Light and Colour”. This provides illustrations and explanations of ways we perceive: (a) reflected light as opposed to transmitted light, (b) matt surfaces as opposed to glossy ones, and (c) the complexities of interreflections. Apart from their intrinsic interest, the function of these in the book is to prepare the ground for the next chapters, which explain how Georges Seurat’s ideas about “painting with light”, either directly or, more often, indirectly, were to revolutionise the use of colour in paintings in a multiplicity of ways. Thus, the next Post will provide a link to Chapter 8, which, after introducing Seurat’s ideas and methods, starts the process of going more deeply into their game-changing ramifications. What follows below gives a foretaste of the nature of these.
Game-changing ramifications
Not nearly enough importance is given to the impact of Georges Seurat’s ideas concerning the depiction of reflected light. Their significance lies in the fact that, either directly or indirectly, they were to have a transformative, game-changing influence on the way later artists:
Painted reflected light.
Approached the depiction of illusory pictorial space.
Explored whole-field colour relations.
Ramped up the colourfulness of their paintings.
Too often in the past the focus has been on Pointillism as a method, treating it as a fascinating, but not so very important phase in art history. In contrast, in my book, I show that the ideas behind Seurat’s innovations, as developed and transformed by his successors, were to open up possibilities of permanent value for anyone who makes paintings of virtually any kind. With hindsight we can see that Seurat’s ideas:
Furnished one of the two pillars that underpin the transformative use of colour found in the work of numbers of progressive artists, including Gauguin and Bonnard. As we shall see in later chapters, when we come to the subject of whole-field colour relations, the artist primarily responsible for the other pillar was Cézanne. It was these two sets of ideas that were to be synthesised in the dogmas of Marian Bohusz-Szyszko.
Opened the way to scientific experiments that supplied coherent insights into the working principles of the eye/brain systems that enable the perception of surface-solidity, surface-form, in front/behind relations and the qualities of light (reflected light and ambient illumination). Since it is the operation of these that make possible the only way that artists can use colour/lightness relationships to deceive viewers into interpreting the content of paintings as existing in illusory pictorial space, it is hard to exaggerate the practical value for painters wishing to represent any of the above mentioned qualities in their work.
To prepare for grappling with all this, it is helpful to be clear about the role that the light reflected from surfaces has in creating our sense of their solidity and our perception of both their form and their interconnectedness.
Three images by artists whose work and ideas contributed to the synthesis of Professor Bohusz-Szyszko
The two practical dogmas taught by the Professor are:
No repeated colour.
All colour must be mixtures containing a proportion, however small, of complementaries.
Seurat : La Grand Jatte (detail) in which the artists demonstrated his idea for “painting with light” by making sure that all colours are optical mixtures containing complementaries.
Cézanne “Old woman”, in which no colour is repeated and, probably, all colours are mixtures containing some proportion of complementaries.
Bonnard: “Interior with Marthe”: No colour is repeated and all colours are mixtures containing some proportion of complementaries.
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Posts relating to other chapters from “Painting with Light and Colour”:
Chapter 1 of my book “Painting with Light and Colour” told of the dogmas of Professor Bohusz-Szyszko and his claim that they were “all you need to know about painting”. It also praised their value as a practical guide.
Chapter 2 is about doubts that arose concerning their theoretical basis. It was the experience of living with these that prepared me for a critical moment in my life. This came several years later while I was reading an article in the Scientific American that had been brought to my attention by one of my colleagues in the Psychology Department at the University of Stirling. The purpose of the article was to present what the author, Edwin Land, fervently believed to be a mould-breaking understanding of the neural computations used by the eye/brain to produce the phenomenon of “colour constancy”. Actually Gaspard Monge, a French mathematician, had beaten him to the post by nearly two hundred years. But this did not stop the contents of Land’s article from being the catalyst to the evaporation of my worries. More importantly, my efforts to better understand the significance of Land’s ideas were eventually to open the way for cooperations with colleagues in the The University of Stirling Vision Group (see below*). Without their help, few of the new insights relating to the use of colour in paintings that can be found in my book would have materialised.
But this is jumping the gun. First click on the link below to access the chapter on the doubts that had haunted me and on the process of questioning they set in motion. Its function is to explain why there is a need for the new ways of thinking and doing that play such an important part in the chapters that follow.
The multicoloured display used for the cover of the “Scientific American”, in which can be found Edwin Land’s definitive demonstrations of the phenomenon colour constancy.
____________________
* More on the University of Stirling Vision Group
Above and in many places in my books, I acknowledge the importance of the role of colleagues in the development of the new science-based ideas put forward in them. In particular I mention cooperations with various scientists at the University of Stirling. The most important of these were:
Alistair Watson (Physics, psychology and computer imagery).
Lindsay Wilson* (at the time working on aspects of visual perception).
Also, although Peter Brophy* did not join our group, he was an ever-available and important source of information on the biochemistry of the brain.
In the Autumn of 1984, Alistair, Leslie and I took the first steps in the setting up of the University of Stirling Vision Group, which was to have many meetings attended by the above named colleagues and other members of the various interested Departments. Its starting point was a package of ideas developed by Alistair and myself, and two core algorithms based on them, produced by Alistair. These were:
A “colour constancy algorithm“, capable of modelling both spatial and temporal colour constancy, which was inspired by our interpretation of how this phenomenon is achieved by human eye/brain systems. As a preliminary step to achieving this main objective, the algorithm has to pick off the information about surface-reflection. Since it was obvious that the reflected-light contained information, we speculated upon how it might be used by the eye/brain. Due to my interest in picture perception, we focused on its potential for computing surface-form, in front/behind relations, and the wavelength composition of ambient illumination.**
A “classification/recognition algorithm”, based on our interpretation of how human eye/brain systems achieves their primary task of enabling recognition.***
We could not help being excited by the early tests of these algorithms and the speculations concerning their potential. In our enthusiasm to push matters further, Alistair suggested we should seek the help of other researchers, particularly ones with expertise in:
Mathematics and computing.
Visual perception with special reference of visual memory.
It was at this juncture that, having decided on a name for what we were hoping would become a collaborative group, we contacted Leslie Smith for his mathematical and computing skills. But this was only a start. Once Leslie was on board, we approached Bill Phillips, whose long standing interest in visual memory had led him to take the plunge into the recently emerging domain of neural networks and learning algorithms. After many Vision Group meetings, much sharing of ideas, many hours spent working on implementations of algorithms, and the writing of a number of working papers, we decided to submit a suite of five grant applications to the Science and Engineering Research Council, who had let it be known that they were looking for groups of researchers working on the use of computers to model the functional principles of neural system. The stated aim of the SERC was to set up a small number of “Centres of Excellence” in this domain. Not only were two of our grant applications accepted (one submitted by Bill Phillips and one submitted by Leslie Smith), but also our university was encouraged to create a brand new Centre for Cognitive and Computational Neuroscience . This empire absorbed the University of Stirling Vision Group which ceased to have an independent existence. Its coming into existence also coincided with my departure from Stirling on my way to founding my Painting School of Montmiral, where I intended to put theory into practice both in my own work and in my teaching. I also had hopes of confirming and, with any luck, extending the theory.
__________
* The links to Bill, Leslie, Lindsay and Peter relate to their current status. Alistair, Karel and Ranald all retired or died before the Internet became the essential information source it has since become.
** My book is full of examples of how fruitful this speculation proved to be.
*** In 1987 Alistair published: “a new method of classification” in Pattern Recognition Letters, Volume 6, Issue 1, June 1987, Pages 15-19
It is well known that the Impressionists and their immediate successors (often referred to in my books as the Early Modernists) reacted strongly against what they saw as the straitjacket of the traditional ideas taught in the academies. The purpose of this Post is to publish Chapter 4 of “Painting with Light and Colour”, which provides a short introduction to what these actually were, with comments on the pros and cons of following them uncritically. Normally, I have been writing a separate introduction for my Posts but on this occasion I have used the Introductory from the chapter itself. Accordingly, when you open the link to the chapter below, you may want avoid reading the same thing twice.
Traditional ideas and their limitations
This chapter has four main purposes. These are to:
Introduce some traditional ideas about the depiction of space and light.
Discuss their limitations.
Suggest that these are more comprehensive and satisfactory alternatives.
Prepare the way for a better understanding of the significance of Seurat’s science and his colour based innovations.
The first of objectives is met by elaborating on three aspects of painting which, after being explored in some depth by the Renaissance artists, became embedded in the academic tradition. Although satisfactorily serving their purpose for the artists who followed them, it was these that were found wanting by the Impressionists. More importantly in the present context, it was also these that were given a new dimension by Seurat and those who built upon his ideas. The three aspects were detailed in the last chapter:
Whole-field lightness relations (chiaroscuro) as a means of introducing a sense of the quality of light in the space that is being depicted (Leonardo da Vinci, Titian, Vermeer, Rembrandt, etc.).
Significantly, as we shall see, it is only with respect to the first item on the list (atmosphere) that colour of any sort was seen as having a role to play. Even then only blue was required.
In contrast, the academic rules guiding the depiction of the quality of light and shading provided no function to colour. The practice of the Renaissance artists and the teaching of the Academies placed the emphasis exclusively on variations in “lightness” (what the English call “tone” and the Americans term “value”).
The science referred to in the title of this post had a lot to do with the revolution in the understanding that gave birth to what we now know as the science of “visual perception“. The first intimations that an important change was afoot came in the later part of the seventeenth century with Isaac Newton’s work on the composition of light. However, the paradigm shift came in the late eighteenth century when the work of Gaspard Monge and others made it clear that colour is not a property of surfaces but is made in the head. This completely new understanding of the nature of visual perception was to be fleshed out in the next century by a flood of confirmatory studies. A milestone was the publication by Herman van Helmholtz of a three-volume review of the new domain of study. It was a magisterial achievement that showed why, despite his considerable debt to others, he has been described as the “Father of the Psychology of Perception“. The third and last of these volumes was published in 1867, just in time to have a profound influence, first on the young Impressionists and, then, in the remainder of the nineteenth and in the early twentieth centuries, on many of their Modernist Painter successors.
The new science misrepresented
One of the purposes of “Painting with Light and Colour”, my book on the theory and practice painting, is to provide a better account of the hugely important role of the new sciences of vision and visual perception in the history of painting. In this post I am publishing Chapter 5, which continues the process of setting the scene started in the Introduction to the science at the beginning of the book. It does so by revisiting and shedding new light on important aspects of colour theory. It has four objectives:
To question the widespread dissemination of half-truths and falsehoods in how-to-do-it books and articles on painting.
To sort out misconceptions about colour theory that I have found to be common amongst my students.
To show how well-known concepts are given new significance when considered in the context of the realisation that colour is not a property of surfaces but is made in the head.
To introduce other more recent ideas that will play a key role in the chapters that follow. These are likely to be unfamiliar to most people, as they are the fruit of little known, late twentieth century experimental clarifications, which enable sense to be made of formerly unsolved mysteries.
Two earlier Posts draw attention to the historical importance of Seurat’s science-based ideas on the practice of painting light and colour. In the “Venetian Colourists”, it is argued that the artists known by this label and those who built upon their ideas were not “colourists” at all. Rather they were “lightists”, whose reputation as “colourists” was based on their mastery of whole-field lightness/darkness relations (“chiaroscuro“). Colour did not enter into the theory of painting light until Seurat introduced his idea of using optically-mixed arrays of separate dots of complementary pigment-colours to give a new kind of luminosity to his paintings. This step proved to be the precursor of a transformative jump from “lightists” to “colourists”.
The next steps, which were were taken by such artists as Cézanne, Gauguin and Bonnard, were later to inspire the synthesis of my teacher Marian Bohusz-Szyszko. It is these that provide the main subject matter of the second post mentioned above, namely “The Dogmas, Chapter 1 of my book “Painting with Light and Colour”. There I explain how, as well as having an abiding influence on my own painting and my teaching, they were to:
Provide the questions that led to my scientific research into the perception of surface, space, light and harmony in paintings (see link below).
Lead to the gamut of practical insights on the use of colour in painting that distinguish my books from others on the same subjects.
Figure 1 : “Marian Bohusz-Szyszko, “The raising of Lazarus”
An introduction to key ideas
To help readers to navigate the considerable quantity of unfamiliar science-based ideas contained in my book “Painting with Light and Colour”, I decided to preface its main content with an “Introduction to the science”, which can be obtained by clicking below.
The purpose of this Post is to make available “the nature of painting, “Chapter 3” of my book “Painting with Light and Colour”. It provides a quick run through some basic factors, which are so evident that some of their practical implications are too often overlooked. These are presented under four headings:
Real surface/illusory pictorial space ambiguities.
Whole-field colour/lightness interactions.
What paintings can do that nature cannot.
The human element.
All the chapters in my books have an “Introduction”. Below is the Introduction to Chapter 3. You can choose to read it now or when you click on the link to Chapter 3 that follows it.
Introduction
It is difficult to imagine a more useful first guide to painting than the dogmas of Professor Marian Bohusz-Szyszko. However, they have their limits. Fortunately, as I believe the remainder of this book will make clear, it is both possible and worthwhile to go much more deeply into the reasons for both their strengths and their limitations. One approach to doing this is to trace the roots of the Professor’s assertions by reference to the work and ideas of his artist predecessors. Another, is to focus on the history of science and how it illuminated the subject of picture perception. Whichever our choice, it is inevitable that there will be much overlapping. The reason is that, in the nineteenth century, a particularly high proportion of the ideas influencing the community of progressive artists were rooted in the new ways of thinking about the world we live in that were emerging from science.
To prepare the way for the combination of theory and practice which provides the subject matter of the remainder of this book, this chapter offers a first introduction to basic factors that are necessarily in play when selections of artists’ pigments, mixed with various mediums are arranged on a circumscribed, flat picture-surface in such a way as to excite the feelings of people. The main reason for starting with these fundamentals is because:
Taking them into consideration can help artists to achieve a surprising number of widely sought after goals.
They provide reference points and context for so much of what follows.
Their importance is too often overlooked by practicing artists.
The basic factors in question will be presented under the headings,“real surface/illusory pictorial space ambiguities”, “whole-field colour/lightness interactions”, “what paintings can do that nature cannot” and “the human element”.
