Designing a Visualization - Visual Intelligence - page 24

green/blue, or RGB. Several things are important about the RGB encoding
scheme for colors on computers:

uu RGB does not adequately cover the spectrum of visible light. To test this,
simply compare a photo of a sunset to the real sunset, and the differences
between the two will be very apparent.

uu Human perception of color is skewed. Red, green, and blue are the most
readily perceived colors because they match to the cones in the eye, but
not in direct proportion. Reds and greens are much stronger than blue,
and the cones are more centered in the eye, whereas blue is more in the
surrounding areas of the eye. This has led to the use of red and green in
most indicators, mostly notably traffic lights.
uu The differences between rods and cones in the eye are beyond the scope
of this topic, but a nice explanation is available at www.cis.rit.edu/
people/faculty/montag/vandplite/pages/chap_9/ch9p1.html .

The default color schemes implemented by the Microsoft toolset can be
problematic. Both Excel and Reporting Services allow for a great deal of
control over the colors used, but PerformancePoint and Power View do
not. The website http://colorbrewer2.org/ (s hown in Figure 2-13), gives
great recommendations for different color scenarios.

F I g u R e 2-13 Colorbrewer