Colors are an effective medium for communicating meaning.
Some have certain implicit psychological associations. Red, for example, is often associated with power, love, and anger. Blue might convey coldness, calm, or logic, depending on the context. Different shades of a single primary color can convey vastly different meanings and emotions.
Two or more colors together can have a profound effect on one another. They can be complimentary, or work in juxtaposition.
In data visualization, color sets the tone and enforces a message for the underlying visual display. It creates a certain atmosphere and can turn an unassuming visualization into an emotion-filled data story.
Of all the design elements in a given data visualization – the headings, the analysis, the comparisons, and so on – color is arguably one of the most important and can speak to your audience in many ways.
Using color to evoke emotions
Colors can evoke a whole host of different emotions – from optimism, confidence, strength, and friendliness, to defiance, fear, anxiety, and boredom.
The emotional connection of each color, in part, is cultural, so you want to be mindful of that in how you display information. In the West, purple, for example, is typically associated with wealth and luxury. In Thailand, however, the association is one of mourning.
Have a look at the example below by Keith Dykstra who created a visualization focusing on countries that invested more in research and development than most other countries. Keith uses a greenish-blue color to highlight the countries that are at the center of his data story and labels them ‘Innovation Giants’. The color and positive connotation of those words set the tone for the audience.
For negative results red, orange, purple and generally darker and muted colors often feature in data visualizations.
Justin Davis’ dashboard about flu seasons is one such example. Justin uses dark purple to highlight 2017-18 as being the worst flu season in the United States. The additional coloring of the title ‘PANDEMIC’ – white, set against the emphatic purple background – adds impact and sets the tone for the visualization. The purple sits in stark contrast to the surrounding grey tones and draws the eye of the audience.
Creating associations through color
All of us associate certain topics, brands, locations, foods and other objects or concepts with color. And these associations can help you bring information to your audience more easily, make it more accessible and memorable.
Examples of color associations include political parties, holiday destinations, environmental topics and many more.
One such visualization comes from Klaus Schulte, who visualized data about the Olympic sport of Luge, a discipline that appears to have been dominated by German competitors. Klaus made a conscious decision to color the different competition categories in the colors of the German flag.
The color pattern leads to immediate recognition, and creates an immediate connection with its audience.
A visualization of how the Germans have dominated the Luge at the OlympicsKLAUS SCHULTE
Highlighting the most important aspects of your message
Color can often be made conspicuous by its absence.
I tend to keep all contextual data in shades of grey to ensure that data points are visible, and do not distract from the key insights.
Using one or two colors in this way also allows you to connect certain key metrics to specific colors and helps your audience to recognize these indicators easily.
In his visualization about Malaria in Zambia, Daniel Caroli chose to highlight a single district in red to show how much it differs from the rest. Sinazongwe, a district located near bodies of water, has an extremely high rate of malaria cases compared to the other districts.
Daniel carries that message through his dashboard by applying color only for Sinazongwe while showing all other districts in grey for context.
The impact of color
Applying color to different parts of your visualization lets you tell a more effective story, one that engages your audience at an emotional level and captures their attention quickly.
Well-chosen colors reduce the time to insight for your viewers and helps them understand your message sooner and more easily.
Getting it right takes practices, so I encourage you to try different ways of using color in your visualizations and to take a critical look each time, assessing whether it communicates your message effectively.