Color

An understanding of color attributes, dimensions and characteristics is essential in creating effective visual messages and visualizing information. Color affects viewers attitudes and responses to images, objects and environments. Through proper color use, a viewer's experience and perceptions can be enhanced, directed or manipulated.

Color can be broken down into three dimensions:

Hue: Color sensation by which the viewer distinguishes the different parts of the spectrum: red, blue, green, yellow, etc, There are three primary hues, yellow, red and blue, by mixing appropriate amounts of these pigments almost any color can be produced.

Value: Relative brightness, from light to dark, tonal variation of a hue. Value is an achromatic dimension

Saturation: Relative purity of a color from the hue to gray

There are psychological and cultural associations to color that affect our reading or decoding visual phenomena. The most common associations to hues are, yellow: light and warm, Red: emotional and active, Blue: passive, soft, cool. In associations with each other new meanings take over, Red is subdued when mixed with blue and activated when mixed with yellow High saturated colors are preferred by folk art and children, the less saturated the color, the more restful. The more saturated the color the more emotionally charged.

The following examples are representative of information visualization in which the phenomena of color was intended to enhance the clarity of the message. We will examine:

Japan Sea Map
The association we make about blue for water and yellow-brown for land is utilized in this effective graphic to convey ocean depth and land height. The use of color is consistent with the message. The scale-key is appropriate and clear. The darker the color the higher the land or the deeper the sea, so the color values smoothly cross zero as white. The use of color value to communicate quantity is effective. The complentary colors emphasis differences, while the low color saturation and change of value reduces the vibration.

Altitude Map
This map displays land height. In contrast with the previous map, the use of color here is not as effective in terms of accuracy. The scale-key uses two different colors (hues) in addition to different values of the two colors to communicate land height. The variations of value are not clear. There is high saturation of green and black , making the edges of the shape vibrate. The association we make with green is consistent but the black background doe not enhance the graphic.The green is consistent but the black background does not enhance the graphic.

3D Stock Survey
This map records Investments in stocks per state and per zipcode. The scale-key is not clear, is hard to understand the units so is hard to understand the use of color. There are two values of the same blue, two colors that are analogous (red and orange) and two different variations of green (in hue and value) In addition to the colors of the scale, the small bars have another value of the color to communicate depth. There is no association between the colors and the quantity assigned to them except for red that seems to be the highest quantity and stands out from the other colors. All blue and red are more saturated in the scale key than in the map.