COLOR IN CARTOGRAPHY Four color characteristics important in thematic mapping, meaning the psychological and aesthetic aspects of printed (NOT digital) color. Color Perception Sensing and cognitive processing of color Color Specification Systems The exact naming of colors Design Strategies Use color to its fullest potential in map communication Cartographic Conventions Qualitative and Quantitative conventions

COLOR IN CARTOGRAPHY COLOR PERCEPTION Is more difficult In low light (limits perception to achromatic) On tiny objects (< .06 inch at distance of 12 inches) For people who are color blind Is affected by Light sources (solar, flourescent, tungsten bulb) Object surface (media)

COLOR IN CARTOGRAPHY COLOR PERCEPTION HUE Name of the color we perceive – red, green, blue, etc. Most color wheels have 8 – 12 hues, no more than 24 The most complex maps (soils, geology) generally have ≤ 12 hues

COLOR IN CARTOGRAPHY COLOR PERCEPTION VALUE Lightness or darkness of color Also called tint, shade, tone Created by adding white or black to a hue ≤ 5 values of a color are the most that can be easily distinguished on a map Discrimination depends on background color – dark vs. light

COLOR IN CARTOGRAPHY COLOR PERCEPTION CHROMA Saturation, intensity or purity of the color Varies by adding pigment to gray Chroma varies from 0% (neutral gray) to 100% - pure (maximum color, no gray) Hue affects chroma level – intense yellow appears brighter than intense blue-green

COLOR IN CARTOGRAPHY COLOR PERCEPTION Perception of a color is modified by its environment: Simultaneous contrast – adjacent colors appear lighter in the direction of the darker color, and darker in the direction of the lighter color Successive contrast – same color may appear lighter against a dark background, and darker against a light background

COLOR IN CARTOGRAPHY COLOR PERCEPTION Warm colors: longer wavelengths – red, orange, yellow Cool colors: shorter wavelengths – violet, blue, green Children prefer warm colors, adults prefer cool colors North American adults prefer these colors, in this order: Blue, Red, Green, Violet, Orange, Yellow Greenish-yellow hues are unanimously disliked

COLOR IN CARTOGRAPHY COLOR PERCEPTION For Children’s Maps: Stay in the basic spectrum – blue, green, yellow, orange, red Avoid dull, unattractive colors – stay with spectral hues Children reject the gray scale – avoid achromatic schemes Color saturation should be slightly less than 100% Stick with the expected – water is blue

COLOR IN CARTOGRAPHY COLOR PERCEPTION Colors in Combination: Best combinations result from large difference in lightness (value) between figure and ground Background color must be either light or dark Pleasant figure hues are in blue-green range, or those with little gray Unpleasant hues are yellow to yellowish-green, or those with considerable gray Vivid colors combined with grayish colors form a pleasant combination

COLOR IN CARTOGRAPHY COLOR PERCEPTION Advancing and Retreating colors: Advancing colors appear ‘closer’ to the viewer than retreating colors Advancing colors should be used for figure – retreating colors used for ground Advancing colors = warm hues, high values, deep saturation (deep, dark reds) Retreating colors = cool hues, low values, less saturation (grayish, light blues)

COLOR IN CARTOGRAPHY DESIGN STRATEGIES The Function of Color in Design: Simplifying and Clarifying Agent – differentiate figure vs. ground or unify various map elements Contributes to General Perceptibility – lends legibility, visual acuity, clarity of differences Elicit Subjective Reactions – people respond to color

COLOR IN CARTOGRAPHY DESIGN STRATEGIES Developing Figure and Ground Relationships: Perceptual grouping of colors is a strong tendency – similar hues or brightness, warm or cool colors, etc. Since warm color ‘advance’ they take on figural qualities better than cool colors, which make good ground colors Color combination affects figure and ground development

COLOR IN CARTOGRAPHY DESIGN STRATEGIES Figure Color Ground Color Yellow Black White Blue Black Orange Black Yellow Orange Black Black White White Red Red Yellow Green White Orange White Red Green Best Worst

COLOR IN CARTOGRAPHY DESIGN STRATEGIES Color Provides Contrast: Contrast is the most important design element in thematic mapping Contrasting Hue  clarity, legibility, visual hierarchy Contrasting Value/Saturation  visual interest, quantitative information, high values emerge as figure Render ‘far away’ objects in cool tones, close objects in warm tones Legibility of lettering on maps is greatly affected by both text and background colors

COLOR IN CARTOGRAPHY COLOR CONVENTIONS Qualitative Color Conventions (kind/quality): Stick with hue variations only Blue – water, cool temperatures Red – warm temperatures Yellow/Tan – arid and sparsely vegetated Brown – land surface Green – thick and lush vegetation

COLOR IN CARTOGRAPHY COLOR CONVENTIONS Quantitative Conventions (amount): Color Plan by David Cuff – Use gray and simple hues only Part-spectral – use two colors adjacent on color wheel, plus intermediate hues Full-spectral – use a separate hue for each different amount (red – highest) Double-ended – illustrate positive to negative values by going from one dark hue, through light values, to a second dark hue (i.e. red – blue)

COLOR IN CARTOGRAPHY COLOR CONVENTIONS Quantitative Conventions (amount): Color Plan by Janet Mersey – Series of individual hues Double-ended (same as Cuff) Spectral – includes differences in value and intensity Hue-value – light value of one hue to a dark value of a second hue PMS value – different values of one hue Gray scale – no hues used