The Use of Color

The perception of color is the response of the eye to wavelengths of radiation in the visible spectrum. This response is sent through the optic nerve to the brain, where the stimulus is interpreted as color. There are three main components of color:

• Hue - Position on the color wheel.
• Value - Lightness or darkness.
• Saturation - Intensity of color.

Color is organized into hierarchal relationships called Color Spaces usually defined by the context and the way the colors are mixed. There are two color spaces:

• Additive Color - Physical, pigment-based color, as in paint and ink. The absence of any pigment produces white, and all pigments blended together produces black.
   - Primary colors: Red, yellow, blue
   - Secondary colors: Orange, green, violet
• Subtractive Color - Light-based color, as in computer screens. The absence of any light is black, the presence of all light, or light in the visible spectrum is white.
   - Primary colors: Red, green, blue
   - Secondary colors: Yellow, magenta, cyan

Color has a profound influence in the appearance of user interfaces. The use of color can help to clarify information, indicate a task flow, or draw attention to key aspects of the UI. Color also contributes to the overall branding identity and environmental atmosphere of the visual style. There are several interesting tools available online for working with color. Below is just a small sample of them:

• Color Scheme Chooser by Wellstyled.com
(to the left: color wheel for color scheme chooser)

• Color Blender by colorblender.com •