Keep Things Friendly for Everyone — Colorblind Data Visualizations
As we all know, data visualization represents a powerful tool for conveying complex information in a simple and easily understandable way. By using charts, graphs, maps, and other visual aids, we can help people make sense of data and information that might otherwise be difficult to comprehend.
“Digesting” all those charts and colors is easy for us, but not for colorblind people. There are an estimated 300 million people in the world with color vision deficiency. Some research showed that men are more prone to developing or inheriting this condition.
Approximately 1 in 12 men are color blind (8%), while 1 in 200 women are affected by color blindness(0.5%), which means that a significant portion of the population may struggle to understand certain types and colors of data visualizations.
In this article, we’ll explore the topic of colorblind data visualizations and also provide some tips for designing visualizations that are friendly to everyone.
The effort always pays off, so if you’re curious and read to the end, you’ll find some tools that help you to check how enjoyable are your visualizations of color-blind persons.
What is color blindness?
The term “colorblind” or CVD (Colour Vision Deficiency) may be a bit misleading because most individuals with color blindness can see colors, it’s just their ability to distinguish certain colors is affected (it may be reduced or altered).
Based on studies there are three types of color blindness:
- Deuteranopia (red-green color blindness ) — it’s characterized by the inability to distinguish red and green pigments, these persons are more prone to confuse green with red; it’s the most common form of color blindness that affects almost 99% of people having this affection.
- Protanopia (another type of red-green color blindness) — it's similar to Deuteranopia, but people who have Protanopia cannot perceive red color.
- Tritanopia (blue-yellow blindness) — makes it hard to tell the difference between blue and green, and between yellow and red.
- Monochromacy (no light perception) — when everything is perceived just in shades of gray.
And now it’s time for the long-awaited tips 🧐
By creating dashboards and reports that are easy to read and understand for persons with color blindness, you can also improve their usability for individuals with other visual impairments and those using different devices or in different environments.
Here are common tips for designing charts that are accessible and color-blind friendly:
— Colorblind-safe color palettes: using a pallet that is designed to be accessible for individuals with color blindness is essential. Try to avoid colors such as red and green as much as possible, because they can hardly be distinguished by colorblind people.
— Fewer colors: Don’t try to impress by using a lot of colors; besides the fact that the visualizations will become difficult to read for people with CVD but also for the rest of your audience, you will lose the most important values and your audience will not be able to get the insights you wanted to expose.
— Symbols: if you need to use colors such as red or green, offer alternate methods to distinguish the data using different symbols such as icons, directional arrows, or any other indicators that would give people with CVD another way to understand the meaning of data.
— Labels: including clear and descriptive labels help people with color blindness understand the meaning and context of the data presented. These provide a better explanation and save time not only for colorblind people but also for the rest of your audience; so you can think of it as a win-win situation.
— Highlights through interaction: by using elements like hover-over effects, tooltips, and interactivity, you can make your data visualizations more accessible and understandable for colorblind people, and also improve the overall user experience for all users (again, a win-win situation)
— Different line types (when you have line charts): there are cases when you need to use a certain color palette and the colors are quite similar; to mark important data use solid lines because these are the easiest to see for people with color blindness, and for secondary data, it’s recommended to use dashed or dotted lines. Don’t forget to add a key or legend to explain which line type corresponds to each data point.
— Try to avoid color-coded maps or charts: these types of charts can be challenging for people with color blindness. If you can’t replace them with anything, there are some tips to make color-coded maps more accessible to people with CVD such as using high-contrast color, including text labels, or using patterns or textures.
In conclusion
It’s important to keep in mind that color blindness affects a significant portion of the population and you may never know when a color-blind person may be in your team or audience, so we should strive to make our design accessible to everyone.
So let’s keep things friendly for everyone and create beautiful and accessible data visualizations and give our audience an amazing experience.
As I promised at the beginning, there are some useful tools for creating stunning and colorblind-friendly dashboards and reports:
- Chromatic Vision Simulator (this is the one I use the most) — here is an example dashboard I made and what it looks like on different types of colorblindness
- Coblis — Color Blindness Simulator
- Color Oracle (available for Linux, Windows, and Mac)
- Online Color Blindness Simulators
A site that helps you see how your chosen color palette is seen by colorblind people -> Coolors
Thank you for reaching the end of the article and if you liked it don’t forget to hit the 👏 button, also do not forget you can find other interesting data-related articles on my Medium.
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P.S: If you wanna explore the above dashboard a bit more, you can find it here
