John Bonadies Design Media and Principles: Value and Illusion of Space

Value
Value refers to the relative lightness or darkness of a surface.

Relative is an important qualification here because the lightness or darkness of a shape is largely determined by its surroundings.

Contrast
The amount of difference in value from one shape to another.

High contrast tends to increase clarity and improve readability.
Low contrast tends to put objects in secondary or sub-dominant levels of importance, or used when the message is subtle.

Value Distribution - the proportional arrangement of lights and darks within a composition can affect the emotional impact.

Value and Volume - Using a full range of values within a shape can make a two-dimensional shape object to be three-dimensional.

Value and Space - Dark, crisp shapes tend to advance spatially within a composition from lighter, softer shapes. This is also called atmospheric perspective.

Value and Lighting - Designers can influence the emotional reaction to objects by manipulating the value of an object from different lighting techniques.

Illusion of Space
Linear Perspective
A mathematical system for projecting the apparent dimensions of a three-dimensional object onto a two-dimensional surface called the picture plane.

Objects appear to diminish in size as they recede
The point at which the objects disappear is called the vanishing point
in basic one- and two-point perspective, the vanishing point is at the eye level or horizon line.

One-Point Perspective
When lines recede into space and converge at a single point on the horizon line.

Two-Point Perspective
When lines recede into space and converge at two points on the horizon line.

Three-Point Perspective
When lines recede into space and converge at two points on the horizon line, and vertical lines converge above or below eye level.