COLOR AND COLOR AND PATTERNPATTERN

I. THE NATURE OF COLOR

II. COLOR DIMENSIONS

III. COMPUTER ELECTRONIC DISPLAY COLOR MODELS

IV. COLOR COMBINATIONS

V. COLOR GUIDELINES

Nature of ColorNature of Color

What is Color?

• A product of the mind.

• Spectral color vs. reflected color

Color DimensionsColor Dimensions

• Albert Munsell codified color so that it has 3 separate dimensions:

– hue (color name)– lightness (value)

– saturation (chroma)

Color DimensionsColor Dimensions

1. Hue -- various colors of the spectrum.

• Use less than 12 hues.

Color DimensionsColor Dimensions

2. Lightness (value)

• Difficult to deal with in practice.– intensity not easy to differentiate– intensities look different on different

backgrounds

• Most often used with ordinal data b/c value clearly has some order associated with it.

Color DimensionsColor Dimensions3. Saturation--(chroma, intensity, or purity).

• For any given hue, saturation varies from 0% (neutral gray) to 100% (maximum color).

Computer Electronic Computer Electronic Display Color ModelsDisplay Color Models

• In GIS & computer cartography there are three main electronic display color modeling systems:

RGB Color Model

HLS Color Model

CMYK Color Model

Additive (black to color)

Subtractive (white to color)

Color CombinationsColor Combinations1. The most pleasant color combinations result

from large differences in lightness.2. Good background color is either light or dark.

a. To be pleasant, an object color must stand out from its background color by being definitely lighter or darker (cartography).

3. Pleasant object colors are hues in green to blue range. Hues w/ little or no gray most pleasant.

4. Unpleasant object colors are in yellowish-green range.

6. Vivid colors combined with grayish colors tend to be judged as pleasant.

Color GuidelinesColor Guidelines

• Cynthia A. Brewer, 1994. “Color Use Guidlines for Mapping and Visualization”. In: Visualization in Modern Cartography, eds. A.M. MacEachren and D.R. Fraser Taylor, Elsevier Science Inc., NY, p. 123-147.

Organization based on hue and value, lesser extent saturation

Color GuidelinesColor Guidelines

One Variable Color Schemes

• 4 basic color scheme types:– qualitative

– binary– sequential– diverging

Make sureMake sureeach hue iseach hue issubordinate to thesubordinate to theone aboveone above

Color GuidelinesColor Guidelines

Two Variable Color Schemes

• seldom just use one variable, usually use two or some cases more.

• allows detailed comparisons of distributions.

Shows where variablesShows where variablesare simultaneously eitherare simultaneously eitherhighly or lowly valuedhighly or lowly valued

Dark hues at four corners and vary lightness in between.Dark hues at four corners and vary lightness in between.