COLOR Perception

Sam Francis, Three Colors

An Additive, or Light-based color system, where the three primaries create white

Primaries and Secondaries in a light-based system, where Red, Green, and Blue Make magenta, yellow, and cyan, and finally, white.

Traditional, Pigment-based Primaries

Basic Diagram of the human eye

Rods: perceive value only. Allow us to perceive forms (but not colors!) in dim light.

Cones: perceive color. Require brighter lighting situation to function. Why we don’t see colors as well at night.

This is also why squinting can help to determine what color is lower in value---squinting allows less light to pass through our eyes, limiting the effects of the cones, and our ability to read color. Only rods are working, so we are able to determine value better.

Two theories of how colors are perceived.

• Trichromatic theory: states that there are three different kinds of cones, one for red, one for green, and one for blue-violet (this roughly corresponds to the primaries in the additive color system).

• We see all colors through variations in the amounts of these cones that are stimulated. For example, when perceiving yellow, the red and green cones are activated

• Remember, in the additive color system, red and green mix to create yellow.

Theory two

• Opponent theory: according to this theory, colors are discerned through cone pairs of opposing colors.

• Pairs of cones will perceive red and green OR Blue-violet and Yellow.

• In each pairing, only one color can be seen at a time and the other is inhibited.

After-Images

• This theory may explain the phenomena of After-Images, where, if you focus on an area of saturated color for a long time and then move your eyes, you will briefly see the opposite (according the the subtractive color wheel) of that color.

• The theory suggests, that when a cone is fatigued from focusing on a strong, dominant color, it’s opposite is no longer suppressed.

AFTER IMAGE: when the signaling mechanism for one color is fatigued, its complimentary is no longer inhibited.

After Image is also known as ‘Successive Contrast’

Abnormal color perception/perception deficiencies

Color-blindness occurs in about 7% of men and .04 % of women

Individuals will lack a type of cone and thus be unable to perceive that color

The Ishihara Color test is a tool used to diagnose color blindness

Synesthesia is a perception abnormality where people respond to the environment by combining senses. Shapes may have taste, sounds color, scents, color as well.

These colors are actually perceived in response to sound, smells, etc.

• http://www.youtube.com/watch?v=V3B7uQ5K0IU&feature=related

Primary colors in the Process (printing and photo) system

FACTORS INFLUENCING COLOR PERCEPTION:

• Amount and quality of lighting on surfaces• Visual health/condition of color blindness• The surface of the object:shiny, matte,

textured• The amount of a color• Color relationships: how color is affected by its

surroundings

Different temperatures of light will change our perception of colors

Color Constancy

• The idea that we tend to perceive colors as unchanging, because of our visual memory of objects.

Our brains are able to compensate for color changes that occur due to changing light situations.

LOCAL COLOR:the general color of an object

CLAUDE MONET 3 VIEWS OF ROUEN CATHEDRAL

EXAMPLES OF DIFFERING LIGHTING EFFECTS HOW THEY CHANGE COLOR PERCEPTION

Metamerism

• The capacity of colors to change under different lighting situations

Simultaneous Contrast

• How colors may be effected by color relationships/environment

Richard Anuszkiewicz

Josef Albers

Homage To the Square

Subtraction Effect: A dominant color may seem to subtract itself from a less dominant color a yellow environment will cause a smaller yellow-orange color to seem more orange because it seems to subtract the yellow from the yellow orange

Complementary Reaction/Effect

• A dominant color may seem to make a less dominant color resemble it’s complement.

A strong orange environment causes a blue-green square to seem bluer. This is related to the after-image effect where our eyes become fatigued by one color and spontaneously create it’s opposite.

Value Contrast

• A strong contrast of value between environment colors will cause smaller areas of color to shift in value.

• A middle-value will seem lighter on the dark environment and darker on the light environment.