A triangle is the simplest shape to establish in composition and yet it is one of the most powerful. All it requires is just three points in the visual field, each becoming a corner of the triangle (excepting when the points lie on a line). Unlike circles or rectangles whose points are highly constrained, a triangle's points enjoy freedom of placement.
A triangle can also be created with a minimum of two convergent lines, the third side being formed by the camera frame. Convergent lines abound in nature, most commonly in linear perspective where planar boundaries meet or imply meeting at the vanishing point.
Composition makes use of triangles as a unifying motif when there is little or no control over the shooting environment - as in reportage photography - to add clarity to a visual presentation.
A triangle is made by:
- implication - three points which the viewer's eye connect to closure
- lateral convergence - the top and bottom boundaries of a vertical plane (e.g. a wall) meeting at a horizon's vanishing point
- vertical convergence - the side boundaries of a vertical plane (e.g. wall), when seen through a wide-angle lens, appear to converge at a vanishing point above the plane.
Triangles can take two forms:
Upward-pointing
Where the baseline is at the bottom/front and apex at the top/back. This orientation is associated with a sense of stability with lightness wrought by the diagonals, as compared to the stable-but-heavy rectangular arrangement.
Downward-pointing
Where the apex is at the bottom/front and baseline at the top/back. The inverted position conveys a feeling of instability, dynamism, aggressiveness and movement.
