To learn drawing means to learn seeing.

And: Learning to draw although means to put yourself on a barmy stick.
That sounds good, on the other hand a little bit mystical. But it is easy to explain what is meant.

(If you are in a hurry, jump straight to the “General Hints”, on this site are only theoretical notes!)

Seeing is a highly complex procedure, which mostly takes place in your mind’s eye.
Imagine yourself to a clearing in a forest on a sunny, windy day. You are standing at the edge, flickering lights are dancing over the floor, the leaves of the trees are swichingly moving, the grass is swaying. Suddenly you see a squirrel scurrying up a trunk on the other side of clearing…

When watching a situation like this our eyes are taking up an enormous quantity of information and data, much more than our optic nerves are able to transfer to our brain.

We can estimate the amount of data being really transferred to the brain from the number of cells in the optical nerves and the recovery period of a single nerve. This data-amount is substantially smaller than the information, which is supplied by the cells of the retina. The treatment and interpretation of a seen picture is starting already in the eye, it starts even before the picture is seen. E.g. in the retina contrasts are strengthened by the way the cells are connected (much more information about the borders of areas are submitted than information of the texture of this area, if this texture is regular). The evaluation of patterns like textures or regular moving, for example the weighing of grass and the dancing of the light spots, begins already in the retina and is continued in the brain.

Why do we see a little squirrel in this mass of information, a tiny squirrel, being far away and having nearly the same colour as the trunk, it is running on? Because it is disturbing the regularity of the seen “patterns”. Data processing in the brain is complex and only small aspects are understood up to now. In the brain are cells, which are only activated, when lines of certain angles of inclination are seen. There are structures of cells, which seem to be responsible for geometrical basic figures like circles, triangles and squares (although lines are abstract objects, “in nature” there are no lines, only boundaries of surfaces).

Some examples for “data processing”, when seeing a motif:

• Both eyes supply different pictures. These different pictures are analysed and a "spatial pictures" with detailed space information is processed in mind.
• brightness differences in a motif are balanced. Shades are ignored, objects, even faces are recognized, all the same whether they are lighted from above or laterally.
• Colours are percepted independent to the colour and intensity of the light’s source.
• Objects being equivalent large, but differently far away, are recognized as equivalent largely. Despite the perspective distortions and different sizes of the object’s retina pictures.
• etc....

And all this processing happens with tremendous speed. The eyes are always moving, are focussing several different points during a second, continuously changing point of view, perspective and points of curse and nevertheless (better therefore?) in mind is build a “picture” from this constantly flowing stream of information.

This “picture in mind” has nothing to do with a photo or two dimensional projection (like a drawing). It is much more, it’s a combination of experiences, memories, knowledge and seeing.

The perception processes happens unconsciously. “Drawing naturally” means to go back to the projection on the retina, it means to transform the “picture in mind” back to a simple two dimensional projection on a paper's surface (I am speaking of the “mechanical act” of drawing, artistic drawing is of course much more).

Going back to the picture on the retina needs a special kind of seeing. As draughtsmen I must make myself aware of the unconscious perception processes. I have to control them and often I have to switch them off. I have to suppress achievements, which are normally done unconsciously by me. I have to put myself on a barmy stick.

Some examples:

• A beginner will have extreme difficulties to draw an arm pointing towards him. The arm appears "perspective shortened". A beginner doesn’t see an ensemble of lines with certain gradients and angles, he sees the three dimensional object “arm”, of which he knows that it has a certain size, length and weight and whose perspective shortening is corrected in his mind before he becomes aware of it.
• When drawing two vases of equal size, having different distances to the draftsman, a beginner will draw one to small or the other too large, because he knows, that they have the same size and he cannot see the differences of the projected pictures (during a distance of 10 m).

By the way, some autistic children can draw “naturally correct” being only 7 or 8 years old. That is however a special ability, but it is also the expression of the fact, that they have difficulties in (cognitive) realising their environment. It is an interesting point that these children often lose this drawing abilities, if the autistic disturbances diminish e.g. due to a successful treatment or with rising age.

So learning to draw means to get the ability to switch from a fast and selective kind of seeing, which is optimized for surviving in a quick changing environment to a slow and “abstract” mode of seeing, in which details are noticed and the unconsciously working processing of information is disabled or ignored. Which does NOT mean, that drawing would be a "conscious process", the exact opposite is the case. Similarly to playing an instrument the best drawings are done in a kind of trance.

“Drawing after nature” is also still more. It is, exactly like playing an instrument (or driving a car) a kind of Meditation, and it is an analysis of reality. When drawing, a draughtsman is intensively analysing and capturing his motif for one or two hours. During this time the pencil is logging the traces of his looks (gazes). He is permanently analysing the spatial structures and proportions. And therefore drawing has the same weight for the disciplines, which have to do with shaping in the broadest sense, like mathematics for engineering or nature and society sciences . You will benefit the experiences and abilities acquired when having learned drawing in all cases, where objects are formed, arranged or designed. All the same, whether it is a piece of classic sculpture, a tower of televisions for video art or a skyscraper. You always will benefit, when you have to give aesthetic judgements, always when you have to figure out or to imagine or to rate objects.

All the said above applies to "drawing after nature". But drawing is much more. “Drawing after nature” however is only a tiny range of drawing. You can draw in innumerable ways, with innumerable intentions, materials and techniques. Drawing is the fastest and most personal and experimental way to express yourself artistically. And it’s cheap :-)

A warning:
A good draughtsman will not make automatically good art and for good art you don’t have to be able to draw well. You even don’t have to be able to draw at all to make good art. On the contrary there is a great danger, that a perfect handcraft stifles the artistic expression. Very often a “perfect” drawing is a “dead” drawing. But don’t be afraid, mostly it will do no harm to you, when you know, how to draw well.

Note:
There are different ways to learn the special kind of seing, I was talking about. It is told, that Chinese masters where walking around with their pupils, continuously pointing out certain characteristics and forms of the environment (forms of trees etc.). They didn’t draw, they teached by describing, asking and pointing out and their pupils did the same, asking and describing the forms, they were seeing. In fact, the mechanical abilities you need to hold a brush or pencil, are small. It’s much more complicate to write than to draw. After the pupils had learned to see and describe with the help of the master, they practiced a few weeks the right attitude to hold and drive a brush and then they were able to paint. Nevertheless I am convinced, that active drawing and sketching is the fastest and most efficient way to "learn to see".