Color Schemes Appropriate for Scientific Data Graphics

Color Schemes:  Diverging - Sequential - Categorical - Other

Diverging Color Schemes

Green-to-Magenta, 16 Steps
	Useful for generic diverging data.  Colors can be differentiated by color-deficient viewers.
• Color number text file    • .pdf of color chart    • .png of color chart

Blue-to-Dark Red, 12 Steps
	Useful for temperature-like data, with a subjective interpretation (blue=cold, red=hot)
• Color number text file    • .pdf of color chart    • .png of color chart

Blue-to-Dark Red, 18 Steps
	Useful for temperature-like data.
• Color number text file    • .pdf of color chart    • .png of color chart
Blue-to-Dark Orange, 12 Steps
	Useful for data without a specific subjective color association.
• Color number text file    • .pdf of color chart    • .png of color chart

Blue-to-Dark Orange, 18 Steps
	Useful for data without a specific subjective color association.

• Color number text file    • .pdf of color chart    • .png of color chart
Blue-to-Green, 14 Steps
	Useful for data with a winter (blue) vs. summer (green) association.
• Color number text file    • .pdf of color chart    • .png of color chart

Brown-to-Blue, 10 Steps
	Useful for data with a dry (brown) vs. wet (blue) association.
• Color number text file    • .pdf of color chart    • .png of color chart

Brown-to-Blue, 12 Steps
	Useful for data with a dry (brown) vs. wet (blue) association.
• Color number text file    • .pdf of color chart    • .png of color chart

Blue-to-Grey, 8 Steps
	Useful in particular for diverging data like cloudiness anomalies.
• Color number text file    • .pdf of color chart    • .png of color chart

Blue-to-Orange, 8 Steps
	Useful for data like sea-level pressure, with ansubjective association (blue=low, wet, orange=high, dry)
• Color number text file    • .pdf of color chart    • .png of color chart

Blue-to-Orange, 10 Steps
	As above, with more class intervals.
• Color number text file    • .pdf of color chart    • .png of color chart

Blue-to-Orange, 12 Steps
	As above, with more class intervals.
• Color number text file    • .pdf of color chart    • .png of color chart

Blue-to-Orange Red, 14 Steps
	Useful as an alternative to the red/blue temperature scale.
• Color number text file    • .pdf of color chart    • .png of color chart

Modified Spectral Scheme, 11 Steps
	An alternative to the spectral scheme (no green)
• Color number text file    • .pdf of color chart    • .png of color chart

Sequential Color Schemes

Light Blue-to-Dark Blue, 10 Steps
	Useful for precipitation-like data.
• Color number text file    • .pdf of color chart    • .png of color chart

Light Blue-to-Dark Blue, 7 Steps
	As above, with fewer class intervals.
• Color number text file    • .pdf of color chart    • .png of color chart

Categorical Color Schemes

Paired-color categorical, 12 Steps
	Attempt at a categorical color scale with colors that may be distinguishable to all viewers
• Color number text file    • .pdf of color chart    • .png of color chart

Other Schemes

Stepped-sequential scheme, 5 hues x 5 saturation/value levels
	Useful for portraying levels-within-categories
• Color number text file    • .pdf of color chart    • .png of color chart

Simulations of the appearance of the color schemes to color-deficient viewers were based on algorithms in

• Designing for the Color-Challenged: A Challenge
  T.G. Wolfmaier, Internetworking 2.1 (Internet Technical Group Newsletter) March 1999
  http://www.internettg.org/newsletter/mar99/accessibility_color_challenged.html
  Thomas Wolfmaier's discussion of the issues arising in designing for color-deficient viewers.  Includes a Java application demonstrating the simulation of how different kinds of color-deficient viewers may perceive particular colors specified by the user.

• Java Applets on Colour Vision Deficiencies
  http://www.tsi.enst.fr/~brettel/
  Hans Brettel's applets for simulation the appearance of colors to color-deficient viewers.  See also H. Brettel, F. Viénot, and J. D. Mollon (1997) Computerized simulation of color appearance for dichromats. Journal of the Optical Society of America 14:2647-2655.

The categorical color scheme above, as well as inspiration for some of the other schemes, comes from

• ColorBrewer
  http://www.personal.psu.edu/faculty/c/a/cab38/ColorBrewerBeta2.html
  Cindy Brewer's web application that demonstrates sequential, diverging, and qualitative color schemes (and provides the specifications of those schemes in several different color spaces).  See also:  Brewer, C.A., G.W. Hatchard, and M.A. Harrower, (2003), Colorbrewer in print: A catalog of color schemes for maps, Cartography and Geographic Information Science, 30, 5-32 (http://www.ColorBrewer.org).