Movement created information

The title of  the chapter to which this Post is linked is,“Information created by movement”. It comes from my book, “What Scientists can Learn from Artists”, which is divided into four Parts.

  • The “First Part”  introduces ideas (a) to artists, who are not familiar with the science, and (b) to scientists, who lack a background in art.
  • The Second Part is called “The Evidence”.  It includes chapters on (a) traditional artistic practices (b) my “drawing experiments“, (c) the importance of “movement” to visual perception (this Post), (d) “colour” related phenomena (all but one already posted) and (e) other aspects of vision with profound consequences (already posted).
  • The “Third Part” presents images of neural processes and lists relating to regions of the brain that participate in visual perception. Even though these are hugely simplified and very far from complete, they suggest that something amazing and seemingly unimaginable must be going on in our eyes and our brains.
  • The “Fourth and final Part” goes deep into theory with a view to gathering the disparate strands presented in the preceding chapters into a coherent whole

As indicated above, the link provided in this Post gives access to a chapter that focuses on the role of  “movement” in visual perception.  As in other Posts, I include below a slightly edited version of the “Introduction”, in the hope that it will encourage you to click on the link situated below it, which gives access to the chapter as a whole.

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movement
Read the chapter to which this Post is linked to find how a few milliseconds of  movement can catapult these points of light into two outlined figures at play.

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Introduction to Chapter 10

The studies of blind-sight and unilateral neglect discussed in the last chapter show that visual perception is not the kind of thing that can be understood by introspection alone. Rather, it is the fruit of a labyrinthine concatenation of neural processes, involving activity in large variety of locations within the brain. The same message can be derived from the diagrams to be shown later (in chapters 14 and 15). These provide glimpses of a massively complex system containing a wide variety of neural structures, hundreds of millions of neurons and untold billions of connections between them. This chapter is grist to the same mill. It concentrates on the work of James Gibson, Nicholas Bernstein and Gunnar Johansson, three scientists who extended our understanding of the experience of seeing.

Although many might suppose that movement-generated perceptual cues could have little or nothing to do with drawing static objects from observation, they would be wrong, as made clear in my book on drawing. However, their usefulness in drawing practice is far from the only reason for devoting a whole chapter to them. Thus: Gibson created a new interest in the power of movement-generated cues, Bernstein used elegant mathematics to demonstrate the interdependence of top-down and bottom up influences in the control of visually guided movement, and Johansson produced a demonstration that blew away a multitude of misconceptions.

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CHAPTER 10 – INFORMATION CREATED BY MOVEMENT

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Other chapters from “What Scientists can Learn from Artists”

These deal in greater depth with subjects that feature in the other volumes

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Blindsight & the bakery facade

This Post provides a link to Chapter 9 of “What Scientists can Learn from Artists”, the book that presents the science that supports so many of the ideas and proposals found in my other three books. Its full title is “Blindsight, unilateral neglect and the bakery facade illusion”. It recounts what for me was a particularly exciting adventure into the mysteries of eye/brain function. This had its origins in research I was doing at the University of Stirling, Scotland, and reached its conclusion here in Montmiral, as a result of trying to understand why a student, who was good at drawing accurately, persisted in seeing the slope of a wall top differently from three other people sitting close to him. It turned out to be a question of his being taller than them and, as a result, he was relating the wall top to a slightly different background, with fascinating consequences: Ones which were to provide the substance not only of the chapter to which this Post is linked, but also of a closely related chapter in my book on drawing.*

Blindsight
Piazza del Duomo, Milan, which plays an important role in a fascinating, game changing story told in this chapter.

Two paradoxes

The bringing together information about “blindsight”, “unilateral neglect” and “The bakery facade illusion” provides yet another approach to making  clear that the process of “seeing” is complex. It also presents evidence that lead to two paradoxes, namely that:

  • we can all “see” what we cannot see
  • we can all “imagine” what we cannot imagine”.

Luckily knowledge of eye/brain systems can make sense of these seemingly senseless propositions. Also, it can alert artists to some deep seated problems they cannot avoid facing when drawing or painting from observation.

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As I usually do when presenting book chapters, I am providing below an edited version of the “Introductory” to the chapter in question in the hope that it will whet your appetite for reading the chapter itself.

Introductory

This chapter delves a little deeper into the subject of visual mechanisms and systems. It is one of the most important in the book because it provides information concerning the central problem as to how preconscious, bottom-up processes enable top-down control of the skilled use of eye/hand coordination. The first part takes the form of a detective story. The key to unlocking the mystery lies hidden in two experiments, relating to two visual impairment syndromes, each resulting from damage to a different part of the brain. Though other syndromes can be legitimately given the same names, they will be referred to as “blindsight” and “unilateral-neglect”. The second part of the chapter describes a powerful visual illusion, first noticed in relation to the facade of a building in Castelnau de Montmiral, S.W. France. This is shown to have general implications both for artists trying to depict scenes containing rectangular surfaces and for psychologists of perception, trying to understand the mechanisms underlying analytic-looking.

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WHAT SCIENTISTS CAN LEARN FROM ARTISTS” CHAPTER 9 – “Blindsight, unilateral neglect and the bakery facade illusion”

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*  “Axes of symmetry, recession and the constancies”: A chapter from my book on drawing that shows some of the ways the theory in this more scientific chapter can be related to practice.

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Other chapters from “What Scientists can Learn from Artists”

Like the chapter to which this Post is linked, the links below can be used to access chapters from the middle section of my  book that elaborates on the science behind subjects that feature in the other volumes:

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The other constancies

My two previous  the Posts provided links to Chapter 12, “Local colour interactions” and Chapter 13, “Colour constancy”, from my book “What Scientists can Learn from Artists”. This Post provides a link to Chapter 15, “The other constancies”. Below the two images you will find an edited version of the “Introduction” to this chapter. As with other Posts, if you find that the subject matter interest you, you can click on the link below to the .PDF version of the chapter as a whole. The images illustrate two of the visual perceptual problems with which artists have had to come to terms.

constancies
Cézanne read Helmholtz and took the view that perceived reality is different from the measured reality that his predecessors sought to depict. When he tipped up landscapes and the tops of pots and vases it was because he believed that he was painting what he saw, even if he had to cheat to do so.

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Introductory to Chapter 15

Colour constancy is by no means the only constancy of visual perception. There are many other constancies and all are fundamental to the ability of the eye-brain to make practical use of visually acquired information. Paradoxically, although their name suggests stability, they are responsible for the veritable “shifting sands of appearance” which, in its various guises, constitutes one of the main problems for artists seeking to obtain accuracy in drawings or paintings from observation. This is because they ensure that, when we look separately at any two similar features of appearances whether they be whole objects, parts of objects, sections of contour or colours, there is a very strong tendency to see them as being more similar to one another than objective measurement would dictate – often a great deal more so. Our visual systems upset the measured parameters of external relationship by relentlessly forcing them towards normative dimensions and values. As a result, the constancies involve enlarging and diminishing, squashing and stretching, revolving, darkening and lightening and modifying colour. Any list of the constancies of particular interest to the artist should certainly include (a) size constancy, (b) shape constancy, (c) orientation constancy (d) lightness constancy and (e) colour constancy.

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CHAPTER 15 – “THE OTHER CONSTANCIES”

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Related chapters from “What Scientists can Learn from Artists”

Other Posts on colour and light in painting:

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local colour interactions

Introduction to the Post on “local colour interactions”

This Post is the second that offers a link to a .PDF version of a chapter from “What Scientists can Learn from Artists”. The purpose of making this more scientifically oriented information available on this website is to encourage readers to go deeper the ideas presented in my practice-oriented books on drawing, painting and creativity (see “Contents List” on the “Posts Page”). Chapter 11, the chapter featured here, focuses on new and unfamiliar things of potential value to artists that can be said on “local colour interactions”, a subject that has featured widely both in books and in the classroom. Its father figure is Eugene Chevreul, the Chemist at the Goblin tapestry works, who was responsible for the phrase “simultaneous colour contrast”,  and the best known publications on the subject are by Johannes Itten and Joseph Albers, both teachers at the Bauhaus. Of more recent books covering the subject, I can recommend “Colour : A workshop for artists and designers”, by David Hornung.

With so many authoritative writings on the subject, it might be supposed that I would have little to add, particularly since, as a general policy throughout my books, I have done my best to avoid wasting time on subjects that have previously been exhaustively covered in convincing ways. It is for this reason that my chapter on “local colour interactions” concentrates on subjects that do not appear in the publications of Chevreul, Itten, Albers, Hornung or, as far as I know, of anyone else. What I have to say is based on research triggered by the excellent teaching I received at my art school and issues arising in my own paintings. Its novelty comes either from original or less well know scientific research that deals with matters of potential interest to artists.

 

local interactions
Figure 1 : Nine discs contrasted with different coloured backgrounds, based on an Art School project that not only raised many questions but also triggered further investigations in the context of my own painting.

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The link to the .PDF file

CHAPTER 11-BODY COLOUR AND LOCAL INTERRACTIONS

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colour contrast
Figure 2 : An illustration from a children’s book that led to an interest in colour interactions involving thin lines and over time to a number of surprising discoveries

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Other chapters from “What Scientists can Learn from Artists”

These will be dealing in greater depth with subjects that feature in the volumes on the practice of drawing, painting and creativity.

Published chapters from book 2 of “Painting with Light and Colour”:

That is to say, the one that focuses on issues relating to local colour interactions, as opposed to how reflected-light influences appearances.

Other published Posts on colour and light in painting:

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Colour constancy demonstration

Colour constancy sets the ball rolling

It was unequivocal evidence of “induced colour” and “colour constancy” that triggered the realisation among scientists towards the end of the Eighteenth Century that colour is not a property of surfaces in the external world but phenomenon that is made in the head. Once this idea had been digested, it gained momentum and evidence began to pour in to suggest that all visual experience is a creation of the eye/brain combination. This game-changing paradigm shift was to lead, not only to the birth of the science of “visual perception”, but also to fundamental changes in the practice of artists,  either when drawing or painting from observation or when seeking control of pictorial dynamics. This is why the “constancies” and “simultaneous contrast dynamics” play such an important role in my books on the practice of painting and drawing. It is also an important part of the reason why I have written “What Scientists can Learn from Artists”, the last volume of my four volume series that explains the science behind so many of the ideas elaborated upon in the remaining three volumes. In going more deeply into the subjects that play such an important role in these books about artistic practices, it plunges us deep into the astonishing nature of the working principles of visual perception. Apart from the sheer wonder this must surely generate, knowing about the ways these determine how we “look” and how we “see” should have a significant benefits for artists: The deeper understanding and appreciation of the extraordinary things that are happening in our heads should help artists to:

  • Deal with the many practical problems that invariably face them when drawing or painting from observation
  • Make more creative use of their physical and conceptual tools.

The next Posts I will be chapters from the science volume.

A life changing event

This Post on “colour constancy” is the first from “What Scientists can Learn from Artists”. Its inspiration derives from Edwin Land’s irrefutable demonstration of the phenomenon of “colour constancy”, which proved to be a milestone in the search for an understanding of a subject that turned out to be of key importance to the understanding of how we “perceive surface”, “sense space” and are “aware of of lighting conditions”, all subjects of key importance to the ideas presented in “Painting with Light and Colour”.   

Below are:

  • A photo of the equipment used by Land for his epoch making colour constancy demonstration.
  • A reprise of the “Introduction” to the chapter and a link to a .PDF version of it (no need to read it twice: if you read it below, you can skip it in the chapter)
  • Links to Posts from “Painting with Light and Colour”, all of which (particularly chapters 7 to 11) have a debt to research that grew out of the colour constancy demonstration.

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colour constancy demonstration
Figure 1 : The set up for Edwin Land’s first colour constancy demonstration, comprising a multicoloured “Mondrian”, three light sources, projecting the three light primaries, and a telescopic light meter that could take intensity readings from each patch of colour separately.

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Introduction

As explained earlier, a key event in my life was the encounter with Professor Marian Bohusz-Szyszko. The ideas he shared set me off on a lifelong journey of discovery. My first step was to set about testing his seemingly extravagant assertion that it is only necessary to follow two rules to guarantee a good painting:

    • There must be no repetition of colour on the same picture surface.
    • All the colours used must be mixtures containing at least a trace of complementary.

After four years of experimenting, I proved, at least to my own satisfaction, that there is a special quality in all paintings that abide by these two rules. It is difficult to describe, but it involves the creation of a sense of pictorial space and harmony.

Fortunately, a troubling paradox arose that would eventually have a profound effect on the development of the ideas presented in this book. It concerned the Professor’s physics-based proof of the invariable variability of colours in nature. This asserted that no two parts of any surface will reflect exactly the same wavelength combinations into our eyes due to:

    • The complexity produced by the inter-reflecting surfaces
    • Variations in viewing angles and distances
    • Atmospheric filtering

The paradox is that, if the light reflecting from two parts of a surface can never be characterised by the same wavlength combination, how could artists repeat colours on a picture surface? Even if two regions were painted with exactly the same pigment-colour, how could these appear as the same?

Other people might already have known how to resolve this mystery, but for many years I had no idea how to do so. My first inkling of a solution came after many years, as a result of reading a paper by Edwin Land, the inventor of the Polaroid camera. In it was a powerful demonstration of the phenomenon of “colour constancy” and an attempt to explaining it. What the demonstration showed was a region of colour within a multicoloured display (henceforth referred to as the MCD) being perceived as remaining the same, even when the experimenter changed the combination of wavelengths being reflected from it. I was excited because here were two colours being perceived as the same despite reflecting different wavelength combinations into they eyes? For me it was a eureka moment. However a big problem emerged for it was soon clear to me that the explanation of the colour constancy demonstration suggested by Land was not neurophysiologically plausible. An alternative had to be found. I could never have guessed at the treasure trove of discoveries that would come out of my struggles to provide it. This chapter describes Land’s demonstrations in the context of an earlier attempt at explaining colour constancy. The next chapter introduces our neurophysiologically plausible colour constancy algorithm.

The colour constancy chapter

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WHAT SCIENTISTS CAN LEARN FROM ARTISTS – CHAPTER 13 – COLOUR CONSTANCY

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Chapters from “Painting with Light and Colour”

Other Posts on colour and light in painting:

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colour mixing by layering

This Post provides a link to “Colour mixing by layering”, Chapter 15 of my book “Painting with Light and Colour”. It is the last and longest of the five chapters devoted to colour mixing. Below is a slightly edited reprise of the “Introductory” to the chapter. If its contents make you want to find out more, click on the link beneath to obtain a .PDF version of the whole chapter.

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layering

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Introductory

This long and important chapter deals with the practical problems and opportunities that arise when coats or washes of one pigment colour are layered or otherwise superimposed on coats or washes of other pigment colours. In particular it is about how outcomes are influenced by the degree of translucency or opacity of the pigment-colours used. An important conclusion is that the same factors that are at play in colour mixing by layering are also at play in colour mixing by stirring.

The chapter starts by using the example of oil paints to illustrate general principles that apply to all colour mixing. It progresses to an analysis of ways in which colour superimpositions play out in the cases of watercolour, gouache, acrylic and dry pastel. The chapter concludes with some supplementary remarks on the use of scumbling and glazing in oil paints and acrylics.

CHAPTER 15 – COLOUR MIXING-LAYERING

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The other four colour mixing chapters

Other chapters from “Painting with Light and Colour”

Other Posts on colour and light in painting:

Chapters from “What Scientists can Learn from Artists”

These deal in greater depth with subjects that feature in the other volumes

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Colour mixing made easy

This Post provides a link to Chapter 14 from my book“Painting with Light and Colour”, which is the fourth of the five chapters devoted to colour mixing. Its purpose is to show that all the complications of colour theory proposed and explained in the previous chapters, need not be a barrier to our creativity when it comes to their practical application. Quite the reverse. Below is a  reprise of the “Introductory” to Chapter 14. If its claims make you want to find out more, click on the link beneath it to obtain a .PDF version of the chapter, which will explain how it can be made easy (a) to mix and (b) to make use of any of the thousands of subtly different, complex colours required for exploring the full extent of colour space.

colour mixing

Introductory

Introductory
This Chapter consists of two parts. In the first, a suggestion is made as to why people have been daunted by what they initially perceive as practical difficulties inherent in the approach to colour-mixing adopted in this book. In the second, a description is given of a practical way of getting around the seeming obstacles. At first sight this may appear to involve important sacrifices, but upon further investigation it turns out that even its shortcomings can be interpreted as powerful advantages.
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CHAPTER 14 – COLOUR MIXING MADE EASY.

The other colour mixing chapters

Other chapters from “Painting with Light and Colour”

Other Posts on colour and light in painting:

Chapters from “What Scientists can Learn from Artists”

These deal in greater depth with subjects that feature in the other volumes

 

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Finding a maximum of colours

This Post provides a link with Chapter 13, the third of the five colour mixing chapters I promised to publish in the coming days. Its title is “Finding a maximum of colours”. As with the others Posts on colour mixing, I start by providing an edited version of its “Introductory”.

maximum of colours
Plenty of colours are needed, even for painting a single flower and its context

Introductory

Estimates have been given as to the maximum of colours that can be made from mixtures of the paints available to artists. The smallest of these suggests hundreds of thousands. At first sight such huge numbers might seem to be beyond the reach of artists. However, Chapter 13  explains the theory of why this is not the case, while Chapter 14 shows how easy it is to use the theory in practice. You can read Chapter 13 by clicking on the link below. Chapter 14 will be made available very shortly.

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CHAPTER 13 : FINDING A MAXIMUM OF COLOURS

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Other Chapters from “Painting with Light and Colour”.

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Chapters from “What Scientists can Learn from Artists”

These deal in greater depth with subjects that feature in the other volumes

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Colour circle: Misunderstandings

This is the second of five posts on colour-mixing. Its purpose is to prepare for the three more practical chapters that follow, by putting straight a number of commonly held misunderstandings relating to the ‘colour circle’. Below is a slightly edited version of the Introductory to the chapter, followed by a link to it the whole text.

ken colour mixing

Introductory

At my painting school, I give talks on colour-mixing. The chapter which I am publishing in this Post as well as the next three chapters (all of which I will publish in the near future) are based on these. Between them they both flesh out some of the claims made in the previous chapter and provide a sound and practical approach to colour-mixing. My purpose is to provide help with:

  • Finding a maximum of colours in any part of the colour sphere (as described in the last chapter).
  • Creating a sense of light, space and harmony in paintings.

The first of my talks concerns colour-mixing by stirring (as opposed to colour mixing by layering, which I will deal with later). Experience has shown that for many people coming to my Painting School for the first time, it is necessary to start my explanations at the most basic levels. Accordingly, I introduce my talk by apologising in advance for going over ground that may already be familiar to some, but suggest that it is better to be absolutely sure of building on common and solid foundations.

CHPTER 12-REFINING THE COLOUR CIRCLE

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Other Chapters from “Painting with Light and Colour”.

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Colour mixing: clarifications

Recently I was asked if I could post the five colour mixing chapters from my book “Painting with Light and Colour” (Chapters 11 – 15).  I will be surprised if you do not find that many of the ideas in them are new, interesting and practical. At the bottom of the page is a link  to Chapter Eleven, the first of the four chapters, whose title is, “Colour mixing – definitions and misconceptions”. To whet your appetite (below the image) I have included a slightly edited version of its “Introductory”.

Coloour mixing 1
Figure 1 – A young student exploring some of  the practical colour mixing ideas explained in the four colour-mixing chapters of my book

Introductory to Chapter Eleven

Introductory
At the outset of my life as an artist, my conception of colour-mixing was of a dry and mechanical subject. I thought of it as no more than one of those necessary basic skills that could easily be picked up along the road. To my surprise, nothing turned out to be quite so routine as it had seemed, and one line of enquiry led to another in a most seductive way. Each new development plunged me deeper into the history either of science or of art, until an engagingly coherent story emerged. The result was a practical understanding of a kind that might be difficult to find elsewhere.

“Most how-to-do-it art books have sections on colour-mixing and there are a number of tomes that offer technical information for professionals.  These latter tell us that scientists have understood the physics underpinning colour-mixing theory for a very long time: Certainly they have done so since James Clerk Maxwell’s lecture on colour vision, given at the Royal Institute, two years before the First Impressionist Exhibition in 1874.

In view of the availability of all these  sources of information, it might be thought that there is nothing left to add. Unfortunately, this is far from the case. The problem is that:

  • Too many painters are being seriously misled by the half-truths and even falsehoods which have entered into the stock in trade of popular colour-mixing theory.
    Science has far from stood still since the 1870s.
  • Particularly since the 1970s, scientists have been finding out a great deal of new information about how eyes and brains work and, as a result, have arrived at a number of new understandings that could help artists in practical ways, which are not being made use of by the artistic community.

For these reasons and others, it is clear to me that there is a need for the up-to-date approach to practical colour mixing that is supplied by the next chapters.

One approach to clarifying matters is to place the information presented in an historical context. Doing so reveals that:

  • Some of the best of ideas have been obscured by the passage of time.
  • The evolution of colour-mixing theory, owes much to parallel development of the histories of science and of art.
  • The story of when, how and why artists adopted new colour-mixing practices, provides many insights into their potential uses in painting.

With respect to the links between the discoveries of the scientists of visual perception and the practice of the artists, the evidence is usually sparse and often ambiguous. To compound the problem history (not least the history of science) becomes distorted because it is told by people who write with the benefit of hindsight and sometimes from the perspective of a particular prejudice.

It may surprise some people to find how many famous scientists are credited both with more originality and much more fully developed and rounded versions of their ideas than they actually had. A mismatch of this kind may be suspected in the relation between the confusions inherent in the early development of the ideas developed by Seurat and Cézanne and the neat synthesis of them by Professor Bohusz-Szyszko. Similarly it is unlikely that any of the early Impressionists had as clear a conceptual framework concerning the real surface/illusory space dynamic as was eventually to evolve from their pioneering ideas. While these are very interesting areas for discussion, the process of trying to unearth and pin down exactly what the early pioneers had in mind is a work for scholars. The focus of this book is artistic practice and it is the more refined picture as developed by the more recent artists and theorists that are the most useful in terms of their practical value.

We start a short survey of these by providing some basic definitions as used in this book:

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CHAPTER ELEVEN – Colour mixing – Definitions and misconceptions

Other Chapters from “Painting with Light and Colour”.

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Chapters from “What Scientists can Learn from Artists”

These deal in greater depth with subjects that feature in the other volumes

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