This Post provides a link to “Chapter 12 : Criticisms and answers“, the last chapter of my book “Drawing with Feeling“. It is a short chapter which focusses, first, on possible critiques of the ‘feeling-based‘ method advocated in the drawing lesson and, then, on my responses to them
Drawing is used for making both drawings and paintings. Below I add examples of both made by my students, all of which required the use of drawing skills. Unfortunately, I do not have examples of work they produced before being subjected to the drawing lesson. I am sorry about this because the progress made can be described as either ‘significant‘ or ‘astonishing‘. For example, there are two drawings by dyslexics who came to Montmiral with extremely limited drawing skills (One, when she arrived, was much less skilled than many seven year old children, the other was in despair that he could find no teaching that could help him improve from his current naive-adult level). I wonder if anyone can pick out the images they made. Apart from these two examples, some of the works are by complete beginners, others are by relatively experienced amateurs and yet others are by professionals. Can you tell which?
The first drawing bellow illustrates the struggles that accompany the rigorous training of the feel-system that takes place during the drawing lesson. The second drawing illustrates the immediate benefit, while the other drawings provide a small sample of the variety of ways the students used what they had learnt in the longer term.
The drawing lesson: An example of the lower part of a tree trunk that took two and a half hours of talk and feel-system training to get this far. Notice the multiplicity of the mistakes and corrections.
The drawing lesson: An example of a first, feeling-based, follow up drawing, taking approximately three hours
A drawing of esplanade wall (study for a painting)
Down a pathway (a study for a painting)
Quick charcoal portrait of me, when I was teaching rather than posing
Seated woman reading
Seated woman posing for a drawing class, in front of a fireplace
A bench on the esplanade (a study for a painting)
A ancient door in perspective (a study for a painting)
Drawing of local landscape
Portrait of a young woman
Portrait of a woman
A self portrait of a woman, in watercolour
Looking out beyond the buildings
Still life with yellow teapot
Pathway and trees
Farmhouse in countryside
Dream of logs burning
Sheep’s pathways abstracted
Memory of a magic moment
List of links to already published chapters from the two books on drawing
Having got a feeling for using the “feel-system“, from Chapter 4 , (“The sketch and the feel system“) and experienced the challenge of making use of it when making drawings from observation in Chapter 10, (“The drawing lesson: action“) this ‘Post‘ provides a link to Chapter 11, (“The drawing lesson: conclusion“). Its role is to offer suggestions as to how to follow up and build upon what has been learnt already. In particular, an exercise is suggested that demonstrates the efficacy of the method, both for training the memory and for improving information pick-up speed without losing accuracy. With sufficient practise, these chapters on the “feel system” and its application in the drawing lesson, will enable artists to:
Use literal accuracy as a tool for deepening awareness of appearances,
Harmonise line-production with ongoing feelings.
Extend the meaning of “accuracy” to include any ‘exaggeration‘, ‘distortion‘ or any synthesis that reflects the “reality” of current personal experience.
Albrecht Dûrer: Tenderness exemplified in his portrait of the artist’s Mother. As he wrote, “Love and delight are better teachers than compulsion”.
Auguste Rodin : The many inaccuracies show how a deep knowledge of anatomy can energise a freedom of mark-making. In praise of the rigorous approach of his teacher, Horace Lecoq de Boisbaudran, he wrote: “what luck we had in falling in with such a teacher. Most of what he taught me is assuredly in me still”.
Edgar Degas : A rough looking study, but with everything in its right place. As the artist himself said, “It is all very well to copy what you see; it is much better to draw what you only see in memory. There is a transformation during which the imagination works in conjunction with the memory. You only put down what made an impression on you, that is to say the essential. Then your memory and your invention are freed from the dominating influence of nature. That is why pictures made by a man with a trained memory, who knows thoroughly both the masters and his own craft, are almost always remarkable works.” One of the best statements I know of the philosophy behind the method of Horace Lecoq de Boisbaudran.
Vincent Van Gogh: “I needn’t rush – that’s no good – but I must work on in complete calmness and serenity, as regularly and with as much concentration as possible, as concisely and as pointedly as possible.” He also said, “I would like to be able to draw more freely and with more exaggeration”.
Toulouse-Lautrec: On meeting someone with a face that interested him, said: “Monsieur, it would be doing a great favour to me if you would come to my house and pose for a portrait. It will probably not look like you, but that is of no importance.”
Pierre Bonnard: “You can take any liberty with line, with form, with proportions, with colours, in order that the feeling is intelligible” and “Impulse, which supersedes science is sometimes superior to science, which, in its turn, supersedes the impulse” and “You have to be patient, know how to wait. The emotion will surge up in its own time”.
Henri Matisse: Self portrait: “Underneath this succession of moments which constitutes the superficial existence of beings, and which is continually modifying and transforming them; one can search for a truer, more essential character” and “The effort to see without distortion takes something like courage and this courage is essential to the artist, who has to look at everything as though he saw it for the first time; he has to look at life as he did when he was a child and, if he loses that faculty, he cannot express himself in an original, that is to say, a personal way” .
Self portrait and a quotation from my book: “Fresh Perspectives on Creativity “: “All we can do is get on with being ourselves, knowing full well that our weaknesses can be our strengths and that, even our strengths are no great disadvantage, if we don’t get too uppity about them.“
Below are links to other chapters from my book, “Drawing on both sides of the Brain“, and to related material
The drawing lesson that can be found in Chapter 10 of “Drawing with Feeling“, is the most important chapter in my book on the practice of drawing. All the other chapters either lead up to it or hinge upon it.
The key difference between the method described in this book is that it concentrates on training our capacity for getting a feeling for relativities of length, angle and position of lines drawn on the page. The method was developed on the basis of my research findings, when I was a Senior Research Fellow in the Department of Psychology at the University of Stirling in Scotland. I was later to discover that, despite many superficial differences, my drawing lesson also has much in common with the core ideas of Horace Lecoq de Boisbaudran, the highly influential 19th century teacher. The big difference between his method and mine is that while he emphasises training the memory in a general sort of way, mine, with the advantage of knowing about important 20th century advances, emphasises the aspect of memory that deals with training the “feeling system“.
The drawing lesson in this chapter is a description of the one that I give to individual students. It usually takes about three hours of highly concentrated trial, error and in-depth explanation of why the error has been made. After it, almost everybody, no matter their original level of attainment, will find that they have taken a significant leap forward in their ability to draw from observation with accuracy. The leap forward for beginners is regularly spectacular and many, already skilful, professional artists have been impressed by the improvements in both the speed, accuracy and expressiveness achieved in their drawings from observation. Some idea of their appreciation can be obtained from the “exhibiting artists” section of the student comments page. In the next chapter it will be shown how students can build on what they have learnt and, as a result, make signifiant progress, both in drawings made from memory and in line-production speed.
While the drawing lesson and its follow-ups enable students to surprise themselves (and sometimes me as well) with the progress they make in one day, they will need to follow up with the exercises suggested in the next chapter and in various other places in this book. If they do so regularly, over a period of time, they will find themselves experiencing, over and over again, the advantages of a method that is centred upon the use of comparative looking, used as a tool for expanding awareness, and of the “sensing” of relativities, as a means of guiding line output. The reward will be an ability to create drawings, whether made quickly or slowly, that are enhanced by their new found and personalised, feeling-centred, information pick-up skills.
Converting a live drawing lesson into the written word has inevitable disadvantages, particularly when it is one that requires up to three hours of sustained concentration from both student and teacher. For this reason, however clear my explanations, Chapter 10 was never going to be an easy read. A consequence of this is that getting the most out of it may prove to be hard work. If it does, I hope that you will not let this put you off, for taking as much time as is necessary to understand and implement each and every step will be well worth the effort.
The centrality of feeling
The big differences between the method explained in this chapter and other methods are the emphases on:
Using accuracy as a way of extending awareness, rather than as an objective in itself.
Enabling liberation from widely taught methods that distance us from our feelings.
Sensing as a way of measuring spatial relativities (of size, length, orientation and position on the page).
Coordinating the information pick-up system with the organisation-of-action skills system to enable fast, information-rich results.
Opening up opportunities for “personal expression”, through exaggeration (Van Gogh, et al.), distortion (Toulouse-Lautrec, et al.) and feeling-connected mark-making (Bonnard, et al.)”.
Before attempting to follow the instructions in Chapter 10, it might be well worth revisiting Chapter 4 “The sketch and the feel system“. There, beside elaborating upon what I mean by the “feel-system“, I suggest a number of simple exercises to give you experience of using it.
Below you will find some images and, below them, some links to already published chapters from BOOK 1, “Drawing with Feeling” and from BOOK 2, “Drawing with Knowledge” , both from the two-book Volume that I have written on the practice of drawing: “Drawing on Both Sides of the Brain“.
Six rapidly drawn images in ink and pencil
Illustrating how feeling-centred, personal responses to a pose can be conveyed in the rapidly made drawings
Cats doing what they do best: Creating eye-catching patterns of curvatures, and softening hearts, while lazing around
Catching the energy of unplanned body positions that cannot be trusted to last more than a few seconds
How simple lines can catch a fleeting expression or a chance pose that unexpectedly catches the eye
The main body of my two part volume on “Drawing” is now complete. What is now required is a bridge to the volumes on “Painting”. This is provided by returning to the subject of “accuracy” as a catalyst to “creativity“.
It is common to find artists and teachers that scorn accuracy. These point out point out that all truly accurate drawings would be the same, no matter which artist produced them and that this would be the antithesis of creativity. But nowhere in any of my books is this use of accuracy recommended. What they do recommend is its use as a tool for both ‘looking‘ and ‘feeling‘ in new ways.
The efficacy of the ‘looking‘ part is easier to explain, for the search for accuracy gives us every chance of expanding awareness. This must be the case for it requires us to adopt strategies that reveal aspects of appearance that we normally overlook.
In “Drawing with Feeling“, the first BOOK in this volume, the focus is on two inextricably linked approaches to seeking accuracy:
The analysis of relativities of size, length, orientation, curvature, position on page, etc..
The use of comparative looking to as a means of avoiding the many traps that the processes of visual perception have laid in our way.
Due to the fallibility of human judgement, neither of these can actually achieve total accuracy. But that is beside the point. It does not matter how inaccurate the result, the process of seeking it will have revealed new aspects of appearances and provide opportunities for finding out more about ourselves.
In “Drawing with knowledge“, the second BOOK in this volume, the emphasis is on using linear perspective and anatomy, not as rules for construction images, but as ways of guiding looking strategies. In other words as tools that encourage new awarenesses.
In the next two books, “Painting with Light” and “Painting with Colour“, the emphasis is on how knowledge of light and colour-related phenomenon can help develop our sensitivity to colour in nature and extend and enrich our domains of exploration.
The idea that the accuracy aspiration might provide a bridge to the awakening of new feelings is harder to for some people to entertain. However it necessarily constitutes a voyage of discovery and, accordingly, provides a way of enriching the memory stores that link us to the feelings of a lifetime.
This chapter has a large number of quotations from artists, but no images accompanying them. I am therefore taking this opportunity to rectify this omission and add a few more quotations.
The first three come from artists that were working well before the arrival of the “Modernist Painters”, but who were significant precursors.
The emphasis is on ‘feeling’ and ‘memory’ and the implication that these is a connection between the two.
Jean-Baptiste Siméon Chardin, “Did you say that one paints with colours? Not at all, one merely uses colours. One paints with feeling.”
Edouard Manet, seeking the ‘effortless’ look, is known to have submitted at least one of his models to more than forty sittings. His hope seems to have been to complete his painting in one go, but he is said to have only once succeeded. Except on that one occasion, every sitting consisted of a variably long sequence of “failures”, each of which had to be scraped down ready for another try. Evidently, as one sitting succeeded another, the artist could not but help become more and more familiar with the pertinent aspects of his sitter’s appearance and this familiarity would certainly have influenced the looking strategies he used subsequently.
Claude Monet, “I want to succeed in expressing what I feel”and “No one is an artist unless he carries his picture in his head before painting it, and is sure of his method and his composition” and “Impressionism is nothing but immediate sensation. All the great painters were more or less Impressionists”
Vincent van Gogh: fellow students in the Antwerp Academy were astonished to see him completing fifteen studies of the model while they were still labouring away on their first. In the Dutch artist’s view, “one drawing study on its own does not give full satisfaction, but many of them, even if they come from different sources, mutually complete one another.”He also said, “I would like to be able to draw more freely and with more exaggeration.”
Paul Gauguin “My simple object, which I take from daily life or nature, is merely a pretext, which helps me by means of a definite arrangement of lines and colours to create symphonies or harmonies”. Also, he is said to have remarked that he closed his eyes in order to ‘see’.
Paul Cézanne was far from advocating cold objectivity when he made the statement, “The painter paints, whether it be an apple or a face. Painting is only a pretext for play of lines and colours, nothing more”. According to him “painting from nature is not copying the object, it is realising one’s sensations.” His advice was to “look at the model and feel very exactly… and express oneself distinctly and with force.”
Pierre Bonnard, “Drawing is sensation. You can take any liberty with line, with form, with proportions, with colours, in order that the feeling is intelligible”.
Edgar Degas: “Drawing is not shapes, it is one’s feelings.” and “It is all very well to copy what you see; it is much better to draw what you only see in memory. There is a transformation during which the imagination works in conjunction with the memory. You only put down what made an impression on you, that is to say the essential. Then your memory and your invention are freed from the dominating influence of nature.
After eighty (some say ninety) sittings, Pablo Picasso felt that he had failed to complete his portrait of Gertrude Stein. However, without realising it, during his struggles, he had got to know the features of the sitter’s face so well that, after a period of reflection and gestation, he was able to produce his rendering of it from memory.
Henri Matisse, “Exactitude is not the truth” and “I cannot copy nature in a servile way; I am forced to interpret it and submit to the spirit of the picture” and “I might be satisfied with a work done in one sitting, but I would soon tire of it: therefore, I prefer to rework it so that, later, I may recognise it as representative of my state of mind”
Chapter 21 of my BOOK “Drawing with Knowledge“, entitled “Deformations–muscles, fat and clothes“, is not finished. Many of the large number of images required for illustrating the issues discussed in the text have not been made. Producing them will require several photo sessions with appropriate models. In the past, I have been putting off confronting the complications this will entail, until the book is accepted for publication. Now I have decided to make use of this website edition of the book, to present a preliminary version of the chapter in its current uncompleted form. I am doing so because, even as it stands, the text is important as it goes beyond what you are likely to find in other writings on anatomy.
As its title indicates Chapter 21 discuses issues relating to surface appearances in ways that are routinely omitted in other texts on anatomy. These occur for a number of reasons and the way they influence appearances can be due to a number of causes:
Differences due to the fact of individual variations in properties of muscles
Differences due to the fact of individual variations in characteristics of subcutaneous fat
Pressures on muscles and fat between different body parts
Pressures on muscles and fat between body parts and external objects
Effects of gravity on muscles and fat.
Chapter 21 also discusses issues arising when a model is wearing clothes. In particular,
Identifying regions both where clothes touch the body and where they follow its form closely
Establishing where clothes leave space between them and the body
Discovering how the characteristics of materials and the forces of gravity effect appearances.
Clicking on the link below will access chapter 21 in its current form:
When I have a more comprehensive collection of relevant images, I will be inserting a number of them below on this web page. Meanwhile, I thought you might enjoy the three images I have chosen and the questions that go with them.
The first is a symphony of mark-making by Berthe Morisot
The second is by the same artist. It illustrates how knowledge of anatomy can underpin a masterly and sensitive depiction of human body parts.
The third shows one of my own paintings, in which my feelings for colour dynamics dominated, to the exclusion of any concern about anatomy. The question is asked whether this is a good thing or a bad thing.
Do we need knowledge of muscles or fat?
Here are two paintings by Berthe Morisot that answer this question differently: The first painting with a tentative “no“. The second of them with a resounding “yes“. It had to be, in view of the underlying knowledge of anatomy enshrined in the quality of observation evident in the depiction of the model’s arms. Quite up to the exemplary standard of Edgar Degas.
Berthe Morisot : portrait of young girl
Berthe Morisot : Portrait of Margaret Carr
Can other priorities override need for accuracy?
In the painting below, done in 1965, in the class of Professor Bohusz-Szyszko, I was enjoying testing out my teacher’s assertion that “all the best paintings are based on colour“. As is clearly evident, anatomy took a back seat. The question is “Did this have a good or bad effect on the result?” My answer is indicated by the outcome, which was sufficiently was positive to encourage me to continue with making paintings in the same spirit.
Ann seated. Colour-dynamics were the exclusive motivation in my head.
Three final questions
Looking back at the top of the two Berthe Morisot paintings, do you think her priority was accuracy or expressing her feelings through the extraordinary range of mark-making dynamics she achieved, stretching from extreme delicacy to panache?
Do you think that Professor Bohusz-Szyszko should have added “the feelings” to his claim that “all good painting is based on colour“? For myself, I might have found his dogmatic assertion easier to accept unreservedly, if it had been extended to be, “All good painting is based on both colour and feeling, as expressed through the dynamics of the combination of colour and mark-making“? Of course, the definition of “mark-making” would have to include the deliberate suppression of marks.
What do you think is left out of the above?
Some quotations emphasising the centrality of the feelings:
Jean-Baptiste Siméon Chardin: “Did you say that one paints with colours? Not at all, one merely uses colours. One paints with feeling”.
John Constable: “Painting is just another word for feeling”.
Jean-Baptise Camille Corot (teacher of Berthe Morisot): “Never lose the first impression that moved us“.
Claude Monet: “Impressionism is nothing but immediate sensation. All the great painters were more or less Impressionists”.
Paul Gauguin: “My simple object, which I take from daily life or nature, is merely a pretext. It helps me, by means of a definite arrangement of lines and colours, to create symphonies or harmonies with them”.
Paul Cézanne: “painting is classifying one’s sensations of colour.”
Pierre Bonnard: “you can take any liberty with line, with form, with proportions, with colours, in order that the feeling is intelligible”.
Henri Matisse: “Colours and lines are forces and the secret of creation lies in the play and balance of these forces”.
How head movement can help accuracy in drawings from observation
All the books correctly say that, when using the perspective frame and other traditional devices for obtaining accuracy in drawings from observation, head movement must be avoided at all costs. Teachers also warn students, who are trying to obtain accuracy when drawing from observation, that any movements of the head can substantially change both internal and external relationships in the scene they are depicting. Although what they say is true, their warning glosses over the fact that such movements can be a powerful tool for homing in on accuracy. The purpose of this Post is to provide the link below to “Chapter 17 – Head movement“, which explains why. Below that link I have included a slightly edited version of the Introductory to that chapter.
Having learnt to find the eye-line, we are ready to make further use of theanalogy of the opening window. The purpose of the next two chapters is to become better acquainted with some of the many anomalies of visual perceptionthat regularly plague attempts at accurate drawing from observation. In this waywe will learn to become more sensitive to aspects of appearances that we might otherwise overlook. Three particularly pervasive sources of anomalies are:
Turning the head (whether from side to side or up and down)
The imposition of axes of symmetry by our visual systems.
The constancies of size and shape.
This chapter and the one that follows give examples of each of these, which willappear under three headings: “head movement”, “axes of symmetry” and “theconstancies”. Although for explanatory purposes, it is convenient to treat them separately, we find that any combination of the three can be affecting our perception at the same time. We start with this chapter on “head movement”
Images illustrating head movement
The three images below show three different views of long boundary the wall of the esplanade. They provide a bit of realism to line drawings found in Figures 1a, 1b, 1c & 1d in the Chapter 17, to which this Post is inked.
Long wall to the right
Long wall to the left
Long wall head on
Chapters so far published from
Book 1 and Book 2 of “Drawing on Both Sides of the Brain” (Volume 1 of the series of four volumes)
I have to thank two short women and a tall man for revealing to me that “axes of near-symmetry” are intimately related to the phenomenon of “orientation constancy”. The tall man was looking over a low wall and he was depicting its top as sloping down from left to right. The short women drew it as horizontal. The fact that the man could see a particular field beyond it that the women were unable to see, meant that he was the only one of the three that was being influenced by what I later came to call the “bakery facade illusion”. The women were right that the top of the wall was horizontal. To find why the man was also right, click on the link below to Chapter 18 of my book “Drawing with Knowledge”. Its title is “Axes of symmetry, recession and the constancies”.
Establishing an eye-line is the first step if you are going to use the the rules of linear perspective for constructing an image. The same is true, if you are using the same rules as an aid to drawing from observation. However, whereas its use in construction is straightforward, its use in drawing from observation is far from it. The purpose of this Post is to explain why. Below you will find a link to “Chapter 16 – Finding the eye-line“. I have also included a slightly edited version of the Introductory to that chapter.
After the session in the studio, we move out into the street. From the demonstrations using the opening window, we have learnt that any straight edge that lines up with the eye-line remains horizontal no matter at which angle it is relative to our line of vision. If we are to make use of this knowledge, we need to find the eye-line. As a general rule, students who come to my school assume that this is easy to do, but the evidence of the drawing they make suggests that they are likely to be deceiving themselves.
Making it easy to see the slope of the esplanade wall
Asking for trouble: explanation why in the chapter
Chapters so far published from
Book 1 and Book 2 of “Drawing on Both Sides of the Brain” (Volume 1 of the series of four volumes)
The eye is full of surprises. The biggest ones come from the structure of retina that is situated at the back of it. The purpose of this Post is to provide a link to images and explanatory captions that tell us more about this starting gate of visual processing. At first sight, much of what we find strikes us as bizarre. But, when we delve more deeply, we discover the considerable advantages of the way things actually are. It turns out that nothing would work nearly as well as it does, if things were arranged any differently. The images and their captions will go a long way towards explaining why.
In the process, they will help readers to get a better understanding of how the eye/brain combination makes practical use of the information contained in the ever-changing patterns of light coming into the eye.
The link to the diagrams
Click on the link below to access the images and captions referred to. They are extracted from ‘The Glossary‘ to the four volumes I am in the process of publishing on this website.
Upon leaving the retina, the neural signals travel in two directions. Some go up the optic nerve to the region of the neocortex known as ‘Visual Area 1′. Others take a completely different route that makes contact with the regions of the “Old Brain”. These play a central role in visual perception as we experience it. For example, they play their part in eye movements, spatial awareness, affective responses, multimodal processing, whole-field relations and much besides. Images and captions relating to both these routes will be posted later on this website, in a separate entry, entitled, “Visual Regions in the Brain”.
Images of blood vessels, neurons and and neural processes in the eye.
The human retina contains a very large number of neurons (cells) and a very much lager number of neural of processes providing links between them. It also features a dense network of blood vessels that supply blood to the neural processes. Together these three components make a significant barrier to the passage of any light that strikes the receptors. Until I learnt better, this light-blocking function did not seem to be of much of interest.
What changed my mind was the discovery that the light-sensitive cone and rod receptors that transform light-energy into neural signals, do not face towards the incoming light, but away from it. Consequently, the light coming into the eyes has to penetrate this light-impeding layer of neurons, neural processes and blood vessels, before it reaches the receptors. To add to my surprise, it turned out that the light-receiving end of the receptors is buried in a layer of dark matter. It was some time before I realised how these seemingly bizarre arrangements make possible visual perception as we know it.
The barrier confronting the light that enters the eye
It turns out that the barrier of neurons, neural processes and blood vessels compensates for the fact that the rod receptors are very much more sensitive to light than the cone receptors. The benefit of this state of affairs is that it enables a necessary degree of functional equality between the responses to the incoming light of the two different receptor-types. Needless to say, this equalling up would not take place, if the light striking the less sensitive cone receptors were to be subjected to the same impediments. This explains why the forces of evolution have created a gap in the neuron and blood vessel barrier in front of the region known as the fovea, exactly where the incoming light strikes the cone receptors.
Glare-blindness
If the equalling up process did not take place, the rod receptors would be bleached out whenever the incoming light was strong enough to activate the cone receptors. The result would be a massive degree of glare-blindness in daylight conditions.
Dire consequences
If they were effectively blind, the rod receptors would not be able to participate in daylight visual processing. As a consequence, the neural computations of whole-field relations could take place. One of the many aspects of visual processing that would rendered impossible would be the separation of reflect-light from body-colour. As a result there would be neither colour constancy, nor the use of the information residing in the reflected-light that has been separated out.
If this were so, pretty well all that I have written in my book “Painting with Light” would be nonsense.
Burying the receptors in dark matter
The burying of the light-sensitive receptor heads in the dark matter is easier to explain. It prevents the light from scattering from one receptor to the next and, consequently, reduces blurring.
Figure 1: Blood vessels blocking light from the ‘rod’ photosensitive receptors. The small darker disc is where the light sensitive ‘cone’ receptors are located. Notice that no blood vessels impede the passage of incoming light to these.
Figure 2: This image of a small section of a network of neural processes gives an inkling of an idea of the extent to which these these can block the incoming light. For reasons explained above, the blockage only applies to ‘rod’ photosensitive receptors. It does not apply to the ‘cone’ photosensitive receptors .
Figure 3: A diagram of cell-types in each of the five layers of the retina. The massive numbers of each of these contribute to the blocking of the light arriving at the ‘rod’ photosensitive receptors.
Some numbers and sizes
One estimate for the number of the light-sensitive receptor cells is in the region of 150 million. Although the precise number of neurons and neural processes in the retina is unknown, it is certainly in the hundreds of millions. All this packs into an astonishingly thin layer (less than 0.5 mm) whose extent can be compared to that of a 10p piece.
A reference
If you want a comprehensive account of the component parts and structure of the retina, you could consult the relevant pages of the website of the The National Library of Medicine. You will find them dizzyingly more complex than the grossly oversimplified information given either above or in the ‘Glossary‘ extract.
The purpose of this “Post” is to provide the link (below) to my introduction to “Chapter 14 : Linear Perspective“, the second chapter of “Drawing with Knowledge” (the second BOOK in the two book volume). The main subject dealt with is uses and abuses of Linear Perspective. The chapter explains the purpose for which the rules the rule of linear perspective were developed and how over the years artists and teachers came to use them for other purposes for which they are not suited. It also explains how the rules of linear perspective can be used in new ways. A preliminary idea of what this means can be found in first paragraph of the “Introductory” to this chapter, which I have included below. Also see below for links to all published chapters from “Drawing with Feeling“, the first BOOK in the two book volume.
“Introductory” – from Chapter 14 : Linear perspective
Academic tradition divides the subject of “perspective” into two aspects, known as “aerial” and “linear”. Aerial perspective concerns colour changes due to the influence on appearances of atmospheric particles situated between the eye and an object being viewed at a distance, and is dealt with in a separate volume. In this book attention will be confined to linear perspective. Moreover, to avoid misunderstandings, it is important to stress that no attempt will be made to compete with the many existing texts on this subject which demonstrate that, when properly applied, the well-known laws can enable the construction of moderately realistic images without the need to actually look at anything. As far as I know there is nothing of interest to add to these, although, a great deal needs modifying in many of the texts on the subject which regrettably give us oversimplified and therefore misleading versions of this complex and elegant subject. Rather, in this volume, the laws of linear perspective are treated in a completely novel way: not as a set of instructions for the placement of lines on but as a tool for guiding looking strategies. This transformation is achieved by placing them in the context of ideas coming both from 19th century research into visual phenomena and from much more recent discoveries relating to the functioning of eyes and brains. In PART 2, the subject of anatomy will be treated in an analogous way for analogous reasons.
Some images relating to the theme of linear perspective
Illustrating Brunellesci’s perspective mirror set-up (maItaly : Italian History and Art)
Pietro Perugino, Christ handing the keys to St Peter 1481-1482.
School of Athens by Raphael in the Stanza della Segnatura 1509-1511
Albrecht Dürer – perspective device for obtaining accuracy
A list of chapters from “Drawing with Feeling“, book 1 of “Drawing on Both Sides of the Brain“
