Principles of Design
Balance in design is similar to balance in physics. A large shape close to the center can be balanced by a small shape close to the edge. A large light toned shape will be balanced by a small dark toned shape (the darker the shape the heavier it appears to be)
Graduation of size and direction produce linear perspective. Graduation of colour from warm to cool and tone from dark to light produce aerial perspective. Graduation can add interest and movement to a shape. A graduation from dark to light will cause the eye to move along a shape.
Repetition with variation is interesting, without variation repetition can become monotonous. If you wish to create interest, any repeating element should include a degree of variation.
Contrast is the juxtaposition of opposing elements eg. Opposite colours on the colour wheel – red/green, blue/ orange etc. Contrast in tone or value – light /dark. Contrast in direction – horizontal/vertical.
The major contrast in a painting should be located at the center of interest. Too much contrast scattered throughout a painting can destroy unity and make a work difficult to look at. Unless a feeling of chaos and confusion are what you are seeking, it is a good idea to carefully consider where to place your areas of maximum contrast.
Harmony in painting is the visually satisfying effect of combining similar, related elements. Eg. Adjacent colurs on the colour wheel, similar shapes etc.
Dominance gives a painting interest, counteracting confusion and monotony. Dominance can be applied to one or more of the elements to give emphasis.
Relating the design elements to the idea being expressed in a painting reinforces the principal of unity. Eg. A painting with an active aggressive subject would work better with a dominant oblique direction, course, rough texture, angular lines etc. whereas a quiet passive subject would benefit from horizontal lines, soft texture and less tonal contrast.
Unity in a painting also refers to the visual linking of various elements of the work.