Is there now a generation of art students untrained in the skills needed for learning to see ?

The human visual system is one of the most complex, subtle and sophisticated engineering feats that has been produced in the biological world.

Its accuracy of perception in small scale work is better than any normal measuring device such a ruler or dividers can achieve. For instance, you can at once see the very slightest misalignment of a letter in a line of text.

But most importantly for the survival of our species our visual processing system is able to judge depth, breadth  and distance, the third dimension. Over millennia, it has developed the ability to judge the distance of a bison, for instance, which could provide a next meal, or the approach of a predator for whom the human being similarly provides an opportunity for lunch.

Whilst this facility is greatly enhanced by our sense of touch, at distances further than arms length we have to rely on our eyes alone (with a little help from our ears).

Most people believe that this depends on the stereoscopic view provided by our two eyes. But in fact the advantage of stereoscopic processing is extremely limited. Its powers diminish rapidly with distance.   And in real life we get information from a great many different views not just two, because we can move our heads and ourselves round an object.

So it is not just a question of developing the technology (at present somewhat clumsy) to transfer two views to a screen which enables us to see the 3D structure and form of an object. We need to look at the other clues our eyes pick up in order to judge 3D form and space.

How to show 3D information on a flat piece of paper or canvas is, of course, a problem that has concerned artists for centuries. It was not until the late Renaissance that those such as Leonardo da Vinci were able to find and to master effective answers. They built on real life visual effects that our brain’s visual processing system uses. These can be loosely grouped under two headings:

1)    LINEAR perspective, which is well understood. Many books and other sources of information about it are available. One does not necessarily have to  possess a visual-spatial (3D) mentality in order to access such information  -  that can be done through mathematics (Euclidean geometry).

2)    TONAL perspective, sometimes called “atmospheric perspective” because of its obvious effect in landscape views. This is far less well understood by the general public. But the ability to perceive such clues is something every human brain possesses. You would not be able to catch a speeding bus or catch a run-away horse or dog without that skill.  It is also what artists will use in drawing the human figure, animals, plants, or many other living and nonliving forms. In life- drawing, for example, linear perspective is virtually useless because there are no straight lines or edges in the subject. Changes of plane are soft, gradual,  curved; they turn sometimes slowly, sometimes more quickly, and usually with great subtlety. They are best described by gradual changes of tone (variation in light and dark). The main principles of which are:

1)   All planes facing upwards are light. Over millions of years the human brain has  evolved to become hard-wired to assume that the main source of light is above one’s head i.e. the sun or moon. This conviction is still firmly engrained in our visual processing system even though in recent years we experience light coming from many different directions. If you don’t believe this fact look at a photograph of craters on the moon and then turn the picture up-side-down. You will see hollows changing to hills and hills to hollows as the direction of light changes from one view to the other.

2)   Every plane facing in the same direction is given the same tone.

But one must allow for the fact that the nearer an object is to you the greater will be the contrast between light and dark. Also, the more details will be apparent.

3)   The difference between convex and concave forms can sometimes appear to be ambiguous.   This ambiguity can be avoided by using an effect called “reflected light”. If you place a white ball on a white surface you will see that light is reflected from that surface on to the underside of the ball. The visual processing system will read this as implying convex whatever the colour of the object and even if it is far from an underlying surface.

All these three effects are used by Leonardo, for example, to great purpose; they can describe 3D form on a 2D surface where the viewer, unlike the artist, is restricted to one view. They derive from real life visual effects experienced by the human eye. They are not an imposed “system” applied gratuitously by theorists.

Unfortunately, they seem to be not well understood in the contemporary world; most unfortunately perhaps by the designers of 3D computer images. 

Too many so-called  “visual-spatial” tests are still being published which apparently ignore the principles of tonal perspective as given above, see for example, recent  so called “Spatial tests of Rotating 3D Objects” designed at John Hopkins University in the USA. In the examples given part of each one is painted black, thereby flattening them into two-dimensional silhouettes.

Such muddled thinking from one the most prestigious and forward looking centres for innovation in the field is disappointing , even one might say, alarming.

Do we now currently have a generation of graphic designers who are expert in computer technology but are so unaware of the traditional  methods developed  by artists over centuries that they are unable to recognise the real life visual clues that the eye picks up to make sense of the natural world?

In the first flush of enthusiasm for digital imaging life drawing virtually disappeared from the art school syllabus. Did this leave a generation of art students untrained in the skills needed for learning to see?

It is therefore mainly for those people that it may be worth repeating the Leonardo methods indicated briefly above.   Of course, a lot of innovative techniques have been explored and developed, particularly during the last 150 years, extending these traditional methods. Many of them have been exciting and constructive; some however, have been difficult for the average unsophisticated viewer to understand. 

New approaches inevitably arrive on the scene and many will be welcome. But whatever their characteristics may be they must always take account of the natural visual processing system of the human brain and the basic grammar of drawing which happily is now returning to its prime position in the art school syllabus.

It would seem that the brilliant advances in computer graphics technology still have some way to go before it can equal or better the brain’s natural inherent powers of vision.

Susan Parkinson
ADT