In this article we will discuss the idea of flexibility and how it relates to the ideas of tone and shape.



* Elasticity - is the visual push and pull of lights and darks which, when presented in a cohesive totality, defines the 3-dimensional forms of a portrait.

The human eye can discriminate between many more tone than the 12 we commonly make use of in a drawing. That means that the artist must "trick" the eye into thinking that it is seeing more than is actually on the drawing paper. To this end we must appreciatehow light behaves and values are perceived.

The trick is to maneuver the eye's natural predispostion towards finality, i.e., towards finishing a drawing even if parts are not actually there. But the eye only does that without protest if the flexibility is harmonious. Only then will the viewer emotionally connect.

The subject of creating harmonious flexibility is broad. In this article we limit ourselves to realistic portraiture.

* Tones|Values - are just degrees of darkness and lightness. We commonly limit ourselves to twelve discrete values.

To appreciate how a shape is rendered we need to appreciate how light operates and how values enter into this. There are two properties of light relevant to drawing:

(1) Light travels in a straight line and reflects off surfaces.

(2) The intensity of light diminishes quickly with distance.

From these properties it follows that:

* As a shape turns away from the light source it dims.

* When two planes face the light they will have different values if their distances from the light source are not equal. For instance, the cheek closest to the light source will have a lighter tone than the one which is farther away.

* The lightest light on a shape is the "highlight". The highlight is always on a plane that is directly facing the light source.

* Most of a portrait’s tone is so-called halftone. That is, anything in-between pure white and pure black. Halftone drawing is simultaneously the most enjoyable and the most difficult part of drawing.

* As a shape turns completely away from the light source it gradually descends into shadow, towards totally black (i.e., the absence of light). However, there is more to it.

* There is also reflected light from one plane onto another. Remember, light reflects off surfaces but with reduced intensity. So be cautious not to overdo your reflected light.

* There is also the crown of the shadow which is the darkest value on the shape. This band of darkness lies between the darkest halftones and the reflected light. This band of darkness is called the Line of Appelle. It is major to capture its shape properly because it determines the shape’s volume.

* As a shape turns away from the light, the halftone plane changes have a soft edge. The quality of this edge is decided by many factors the most major of which are the degree of plane change, the intensity of light, and the texture of the surface.

* In portrait drawing there are also cast shadows which are hard-edged and especially dark and are cast by one shape upon another. An example is the one that is cast by the nose onto the cheek.

An excellent exercise for comprehending the idea of flexibility is to draw a white egg. For a more proscribed environment you can build yourself a black box with one side open that fully controls the light of one source and blocks out the light of other sources that could disturb the condition.

In closing, the use of the twelve-value scale together with the above guidelines allows you to produce the necessary flexibility for your objects.