How to Make Article Images and Figures More Accessible
I was recently going through articles in Nature, when one stood out to me. It was titled “Color me better: fixing figures for color blindness.” As someone who has color blindness myself — and who knows three other students and faculty within my department who are also color blind — I thought this article might be of some interest, so I decided to take a quick look at it.
Here are a few of my own thoughts — some of which are variations of those already in the Nature article, some of which are my own — to help make figures more accessible to color blind readers, whether in scientific papers, PowerPoint presentations or in the classroom.
Don’t make figures that rely on color alone to be understandable.
This may sound complicated, but it’s not that hard. For example, if you have two lines on a graph that are red and green, why not make the red line solid and the green line dashed? Or use triangles for the data points of the red graph and circles for the data points of the green one? It takes only a few seconds longer, but can save a color blind reader many minutes of frustration trying to decipher the graph.
Limit your use of reds.
As a widely used color for highlighting objects of interest, red is by far the most common color that color blind people struggle with. If you must use red, avoid pairing it with black if at all possible; as someone for whom red text doesn’t stand out against black text, I, along with most of the color blind population, will thank you.
Be considerate about confusing colors.
In addition to red and black, I (as with many color blind people) can’t reliably distinguish dark red and brown, dark green and brown, lime green and yellow, medium green and orange, blue and purple, or pink and grey. Blue and yellow are a good combination, as are blue and white, light grey and bright red, red and yellow, yellow and black, or even dark red and lime green.
Add more color.
Sometimes the problem color blind people face is that the colored areas are too small to distinguish. In my case, although red text doesn’t stand out from black text, I can easily see a red jacket hung on the back of a black office chair. In the case of figures, consider making your lines bolder, dots bigger, etc.
Label right on your figure.
Instead of using a legend, consider adding text directly to your figure. That way, color blind people don’t have to struggle to match the colors of the legend to the colors of the figure. Additionally, putting labels right on the figure reduces the amount of working memory needed to interpret the figure, which can be helpful for those with limited working memory.
Don’t overdo it with colors.
If the five colors on that graph don’t serve any purpose other than looking pretty, it may be better to remove the colors entirely.
Highlight areas of interest.
This is particularly useful if you’re including photographs in your paper and the color of the object of interest is difficult to distinguish from the background or from another object in the photograph. One solution is to circle or point to the object(s) of interest. Another is to add false color to the thing you’re trying to highlight — for example, if I was trying to highlight an orange cone in a green field, I might lighten the color of the cone somewhat, and darken the color of the grass. If you choose the false color route, consider supplying a true color image next to the recolored one, so that non-color blind people can see what the photograph actually looks like.
Use a color blindness simulator.
One of the best available is Coblis. Simply stick your image into the simulator and make sure that it’s interpretable by people with red and green color vision anomalies, as those are the most common.
Use descriptive figure captions.
While figure captions are useful for anybody to help understand what’s going on in an image, there are cases where a descriptive caption could make the difference between my being able or unable to interpret a figure. Writing a long caption isn’t a problem at all — better to overdescribe than underdescribe. As a bonus, you’ll also be making the paper more accessible for people who rely on screen readers!
In future, all I ask of you is: spend a few extra minutes thinking critically about colors whenever you’re making figures. A few extra minutes of thought and consideration when creating a figure can save a color blind reader a lot of frustration down the road.
Getty image by ipopba
I'm a country chemist with an M.Sc. in inorganic chemistry, currently doing a PhD in materials science. I am also an inorganic chemistry TA with protanopia and (recently learned) cPTSD. I'm also an amateur hurricane tracker with 13-years experience, along with being a sailor, canoeist, hiker, and general outdoorsman.
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