All too often when we think of perspective (the rendering of the illusion of three-dimensionality on a two-dimensional surface), we tend to think only in terms of linear perspective--lines, vanishing points, horizons, etc.
However perspective down through the ages has also been accomplished by artists using others means--aerial perspective, size perspective, colour perspective, overlapping perspective, placement perspective, etc.
Aerial perspective - the dulling down of colour and edges to create the illusion of depth.
Size perspective - large objects in a picture tend to "read" closer than smaller ones.
Colour perspective - dull colours recede, bright colours come forward.
Overlapping perspective - objects overlapped recede, giving way to the overlappers.
Placement perspective - objects placed near the bottom of a canvas tend to come forward while those higher up tend to recede (all other things being equal of course).
Contributed by Lane, Jim
12 October 1997