If we call these variations from a common type in the features imperfections, as it is usual to do, it would seem to be the imperfections of perfection that charm and stir us; and that perfection without these so-called imperfections is a cold, dead abstraction, devoid of life:  that unity without variety is lifeless and incapable of touching us.

On the other hand, variety without unity to govern it is a riotous exuberance of life, lacking all power and restraint and wasting itself in a madness of excess.

So that in art a balance has to be struck between these two opposing qualities.  In good work unity is the dominating quality, all the variety being done in conformity to some large idea of the whole, which is never lost sight of, even in the smallest detail of the work.  Good style in art has been defined as “variety in unity,” and Hogarth’s definition of composition as the art of “varying well” is similar.  And I am not sure that “contrasts in harmony” would not be a suggestive definition of good colour.

Let us consider first variety and unity as they are related to line drawing, and afterwards to mass drawing.

XI

RHYTHM:  VARIETY OF LINE

Line rhythm or music depends on the shape of your lines, their relation to each other and their relation to the boundaries of your panel.  In all good work this music of line is in harmony with the subject (the artistic intention) of your picture or drawing.

The two lines with the least variation are a perfectly straight line and a circle.  A perfectly straight line has obviously no variety at all, while a circle, by curving at exactly the same ratio all along, has no variation of curvature, it is of all curves the one with the least possible variety.  These two lines are, therefore, two of the dullest, and are seldom used in pictures except to enhance the beauty and variety of others.  And even then, subtle variations, some amount of play, is introduced to relieve their baldness.  But used in this way, vertical and horizontal lines are of the utmost value in rectangular pictures, uniting the composition to its bounding lines by their parallel relationship with them.  And further, as a contrast to the richness and beauty of curves they are of great value, and are constantly used for this purpose.  The group of mouldings cutting against the head in a portrait, or the lines of a column used to accentuate the curved forms of a face or figure, are well-known instances; and the portrait painter is always on the look out for an object in his background that will give him such straight lines.  You may notice, too, how the lines drawn across a study in order to copy it (squaring it out, as it is called) improve the look of a drawing, giving a greater beauty to the variety of the curves by contrast with the variety lacking in straight lines.

The perfect curve of the circle should always be avoided in the drawing of natural objects (even a full moon), and in vital drawings of any sort some variety should always be looked for.  Neither should the modelling of the sphere ever occur in your work, the dullest of all curved surfaces.