When we data vis designers with normal vision consider colorblindness, it’s often an afterthought or an unchecked box on an accessibility checklist we got from a client.
For colorblind people, it’s their life. A life that comes with issues, surprises, and a special view. “Magical”, “horrible”, “frustration and exasperation”, “revelation” are just some of the words that were dropped when I asked ten people about their experiences as a colorblind person. That’s what this article is about: To give you somebody to think about when you do set that ✔️ on the accessibility checklist.
This article is the last part of a three-part series on colorblindness:
The first article, published two weeks ago, explains the difference between colorweakness and colorblindness and which color combinations are tricky to distinguish for your colorblind readers.
The second article, published last Tuesday, explains what you can do to make your charts and maps decipherable for colorblind readers – from varying lightness to using patterns, symbols or direct labels.
3 What’s it like to be colorblind
This is the article you’re currently reading! It starts with experiences from ten colorblind people. Afterward you’ll hear from three people in detail, two cartographers and our Datawrapper CEO:
Ten people’s experiences
- Wesley Jones, cartographer green-blind ⬤
- Mark Harrower, designer & cartographer green-blind ⬤
- David Kokkelink, Datawrapper CEO green-blind ⬤
- Anonymous woman, student green-blind ⬤
- Graeme Grimes, bioinformatician green-blind ⬤
- Lee Durbin, data analyst green-blind ⬤
- Peter Cardwell-Gardner, software developer red- or green-blind ⬤⬤
- Aaron Ghitelman, communications advisor red-/green-blind ⬤⬤
- Rob Morton, local government officer red-blind, partially green-blind ⬤⬤
- Kevin Lee Elder, professor of management information systems, who gave talks about colorblindness in data visualization before Achromatopsia ⬤⬤⬤
The different types of colorblindness neatly match the stats: Most of the people I asked are green-blind, which is the most common type of colorblindness. Colorblindness is also very rare among women, and indeed, only men responded to my tweet. Luckily, my coworker Edurne connected me to her female green-blind friend and she agreed to answer my questions, too – thanks, Edurne!
How it is to be colorblind in daily life
The first question I asked these ten people is how their colorblindness is an inconvenience in daily life. The answers differed a lot. From “colorblindness doesn’t impact my day-to-day life” (Aaron) to “it’s a daily inconvenience” (Graeme) to “being colorblind is horrible” (Rob), the people I asked seem to relate differently to their (probably differently strong) problem.
When is it a burden? Here are some of the answers I heard:
- Buying clothes: “I’d like to believe I dress well despite that.” (Aaron)
- Electronic hardware with a single LED that changes from green to red, e.g. a charging LED. “This can be impossible to tell apart.” (Peter)
- Weblinks: If it links to a page you have not visited, it’s blue, if you have visited the page, it’s purple. Also hard to tell apart.
- Text, in web & app interfaces, e.g. red on black. Or in books: “I’m unable to read kids’ books when the text is on coloured backgrounds.” (Rob)
- Talking about colors and doing creative hobbies: “My doctor found out that I’m color-blind around Christmas, shortly before I had to help my uncle selling his leather wares at a Christmas market. I remember being uncomfortable selling coloured leather and being self-conscious about people asking about which colour to take. My colorblindness also used to trouble me when painting. I would be afraid of ‘doing something wrong’. But I have outgrown that. And I still paint.” (Edurne’s friend)
- Sports: “At climbing gyms, I might ask another climber to point out colour coded holds.” (Peter)
- Games: “In the sports video game FIFA, one team will need to have white jerseys and the other one jerseys in a bold color or else I can’t tell what team each person is on.” (Aaron)
- Cooking: “When is my food cooked?” (Rob)
That said, most people explained that they often don’t know that and when they have a problem: “Maybe I perceive colours differently more often than I’m aware of, but it’s hard to know,” Lee told me. And Edurne’s friend explains: “I assume I perceive colors differently often than I think. I mostly become aware of it when someone calls out the name of colors I see. It’s like a weird Aha! moment.”
How it is to be colorblind and to read a data visualization
So how inconvenient is colorblindness when it comes to reading data visualization? Here, too, the opinions differ, from “almost all data viz has poor colors” (Kevin), “90% of data visualizations that rely on colour are difficult or impossible to interpret” (Graeme) and “1 of 3 color-based data visualizations probably cause problems for me” (Aaron) to “professional data vis designers in reputable organisations like the New York Times do very well” (Peter).
And so differ the emotions when colorblind people see a readable or unreadable data visualization: “I jump a little for joy when I see a visualisation with enough differences in its colors,” Rob tells me. And Aaron explains what happens if that’s not the case: “The first reaction is always frustration and exasperation. It’s worse in quarantine where I don’t just have coworkers I can ask to explain the graphics for me.” “When looking at visualizations, I tend to take my time,” Edurne’s friend tells me. “When I so so with other people and they are much quicker in grasping the meaning – that can be frustrating.”
So let’s hear from designers themselves. What follows are three interviews with green-blind people: two with cartographers – Wesley Jones and Mark Harrower – and one with the CEO of Datawrapper, David Kokkelink, who has also seen and created many charts in his life.
You’ll find that they all bring different experiences and thought-provoking views to the table. I’m very happy to be able to share them with you.
I added colors ⬤⬤⬤ as Wesley, Mark and David see them.
Asking Wesley Jones
After publishing the first part of the series, cartographer John Nelson got in touch with me. If he could make me happy with introducing me to two of his green-blind colleagues at ESRI, Wesley Jones and Mark Harrower? Of course he could!
We’ll start with Wesley:
Wesley, how did you discover that you’re colorblind?
I didn’t know I was colourblind until grade 11. I liked doing those Ishihara tests, but thought they were useless because in some you couldn’t see the number.
Ishihara test, named after its designer Shinobu Ishihara, as normal-vision people see it (left) and as Wesley sees it (right).
I told my friend that, and he looked at the book and said there is a number in every one! I remember looking at the tests the next few days, shocked I couldn’t see the numbers. I think my story is somewhat common – that many colourblind people don’t know they are colourblind until much older.
How much of an inconvenience is it to be green-blind in daily life?
I don’t see it as an inconvenience in the big picture. I see it as a gift, because I get to see the world differently. The world looks magically colourful to me, I can’t imagine what it looks like to someone with normal vision.
But it’s still is a bit of an issue at times. Some of the flashing street lights (with only one bulb) sort of look like they could be flashing red or yellow, so I have to really concentrate when I see those. I also happen to like board games, and it is remarkable how many use colours that are hard for me to tell apart. The more important the thing, the more significant the inconvenience.
However, it can’t be that big of an inconvenience, because I didn’t know I was colourblind for the first 17 years of my life. Generally, my kids and I get a big kick out of it when I colour something a little odd.
And as how inconvenient do you perceive your colorblindness when looking at data visualizations?
This tends to be fairly often. Maybe because colour is used as an identifier in the visualization, one notices being colourblind more often when looking at data visualizations.
This is especially true if a legend is used. I have a really hard time looking at that small legend item and matching it to the chart. I have no problem asking for help, but many data visualizations are difficult to interpret on my own. Generally, the difficultly is not in the entire visualization, but between a couple of categories.
Is your green-blindness also a problem when visualizing data yourself?
I don’t have an issue creating maps or visualizations – because I can only see what I can see. However, I am aware that I might be choosing unintended colours. The truer the colour needs to be to reality, the more I make sure I have someone look over my colour choices.
A HLS color wheel as normal-vision people see it (left) and as Wesley sees it (right). “I rely heavily upon colour wheels like this – and I like this design the best as it is the most intuitive and useful for me.”
Occasionally, people tell me certain colours are similar, and I have to make adjustments – it is sometimes hard for me to believe because the ones they pick out look the most different to me.
Someone once told me that my maps have a slightly different look to them, but that helps make them a little unique. I really try to pay attention to the colours I am picking on the colour wheel.
However, I recently found out that when I am designing (maps or drawing) that my blues tend to have a slight purple slant to them. My blue water is often a bluey-purple water.
A watercolour Map designed by Wesley, as normal-vision people see it (left) and as Wesley sees it (right). “I had to change the water a couple of times because it sometimes went too purple.”
Also, green often slips into skin-tones when I am drawing. I am still not sure how that happens so often. [Note from Lisa: Light green ⬤ and a light skin tone ⬤ both look like ⬤ to Wesley.]
What’s your advice to normal-vision data vis designers?
I want people to keep using all the colours available to them (I can only imagine how fantastic the whole spectrum is), but my advice would be to consider the importance of your message. If it is important or you want everyone to see it, consider that a segment of the population may not be able to see it if you haven’t checked it for colourblindness.
Asking Mark Harrower
Like Wesley, Mark is a cartographer at ESRI. He’s been designing maps and graphics for decades. He’s also green-blind – and has lots of opinions. In this interview, Mark explains which color schemes work for maps and which ones don’t (“80% of Colorbrewer”), why data viz got less readable for colorblind people over time (“45 shades of peach”), and how Enchroma glasses have changed his view (“I get it now”):
Mark, you’re a designer. How do you design differently because of your colorblindness?
I think my colorblindness affects my work in four ways:
- I never design with pastels or desaturated colors ⬤⬤⬤⬤⬤ – they’re a complete fail for me.
- I’m a huge fan of grayscale maps with one or two obvious bright accent colors (like this one from Datawrapper, or the DK Books aesthetic)
- I’m not very confident in my aesthetic choices when I have to use color for a client. Things that seem like a good pairing of colors to me seem weird to others – I accidentally use purple hypertext all the time since it looks like a desaturated blue to me.
- Colors have less of an emotional effect on me; I’m less seduced by them in my designs. So to create a “mood” or “feel” for a design I’ll rely on textures and fonts and graphic motives (like Esri’s Newspaper basemap, which is greyscale). Those are more evocative than using colors alone:
Esri’s Newspaper basemap, as seen by normal-vision people (left) and as seen by Mark (right).
And what are you doing differently specifically when designing maps?
I only ever use single hue color ramps (like light red to dark red ⬤⬤⬤⬤⬤) since I can easily see differences in lightness and so can others. Most multi-hue color ramps are too subtle for me to use on choropleth maps, including about 80% of the ones in Colorbrewer. They just look identical to me.
Mark’s view of the multi-hue and single-hue sequential color schemes on Colorbrewer
If I do use multiple color ramps, they’ll be yellow-blue ramps ⬤⬤⬤⬤⬤ or the viridis ramps:
Viridis color schemes, as seen by normal-vision people
Viridis color schemes, as seen by Mark
You’ve been visualizing data for a few decades now. Where’s the scene now compared to back then regarding colorblindness?
I would say things have gotten worse with data visualizations. We now have the double whammy of
- Unclassed data ramps ruling supreme: The whole “let the data speak for itself” philosophy, when in fact five easy to distinguish colors on a map would have communicated the same without the rampant simultaneous contrast issues.
- We are living in an era of super subtle design aesthetic being embraced by all of these 20-somethings (who, as I cynically think some days, are just designing to impress each other and to win next year’s Information is Beautiful awards). The pendulum has swung too far from the garish 4-color neon designs of the 1980s to a too-cool-for-school “just noticeable differences” aesthetic. Those 8 pt fonts and 45 shades of peach aren’t a home run. end grumpy old guy rant>
How does your colorblindness help you when designing?
As designers, we spend way more time designing our stuff than our audience will spend reading it. Often they’re only marginally interested in our work; they’ll just “glance” at it (as the New York Times and others have learned from their metrics).
Colorblindness is a good surrogate for such an audience. Making sure it works in 1-3 seconds “at a glance, as I scroll past in my newsfeed” is analogous to making it work for folks with bad color vision, or folks who can’t see fine details and small fonts. “Keep it simple and obvious”, works for both vision issues and semi-disinterested audiences.
Last but not least: Do you have any advice for data vis designers?
My advice is always the same: Stop so highly favoriting just one of Bertin’s visual variables (hue) to distinguish differences in kind. Better yet, double-up with other visual variables to do the heavy lifting (combine both shape and hue, or hue and lightness, or…). That is just better design, less error-prone – not just for us colorblind individuals. I always tell my students: Print in greyscale? Still understandable? You’re bullet-proof.
My thinking on this has been influenced by having both indoor and outdoor Enchroma glasses for the past 3 years. They’re not a fix, I still can’t pass Ishihara tests, but OMG WHAT A REVELATION. Literally life-changing to see purple and pink and peach for the first time. And the green in traffic lights! The most unexpected thing was how much more luminous and intense hues are…like safety-vest-orange. It’s ridiculous. I get it now.
Asking David Kokkelink
David is the CEO of Datawrapper, the company I work for. That he’s also one of the 1% of men who have green-blindness (Deuteranopia) is something I didn’t know for a long time, and that most of our team never notice. I was curious if/how this affects him in his daily life and when looking at data visualizations.
David, how and when did you figure out that you’re green-blind?
I first noticed when I was about 3-4 years old, when I asked my parents why everyone said the grass was green ⬤ when it was clearly red ⬤. The next instance I remember was identifying green traffic lights as white ⬤.
Left: What people with normal vision see. Right: What David sees. Photo by Jos van Ouwerkerk, Pexels.
I got a formal diagnosis at an eye doctor that it was “green-blindness” when I was about 12-13 years old.
How inconvenient is your colorblindness in daily life?
It is not a major problem. It makes me rather conservative with color choices for things fashion or furniture (my closet is full of black ⬤, white ◯, grey ⬤, and maybe dark blue ⬤ clothes).
One interesting side-effect of color blindness is that I can never remember what colors things are, even for colors that I should be able to distinguish. I think since my color vision is unreliable, I have sort of unconsciously trained myself to not pay any attention to color at all. Practical example: I’m sitting in my living room right now. Next to me is my bedroom. I couldn’t possibly tell you what color my bed is from memory. Probably grey or dark blue or something. I know it’s rather on the dark side, but I have no clue what color it is specifically, even though I see it daily. This is occasionally an issue when people think I just don’t care, like forgetting eye colors of girlfriends, etc.
How inconvenient is your colorblindness when looking at data visualizations?
Left: What people with normal vision see. Right: What David sees. Map by the German Meteorological Service.
I’d say 90%+ of problematic instances occur when people are going for some sort of ‘traffic-light’ indicator of red ⬤ / yellow ⬤ / green ⬤.
I do think that ‘modern’ data viz practitioners get this right most of the time. The terrible examples were typically found in schoolbooks or government publications, and generally, look like they were done with Excel 95.
What’s your first reaction when encountering a data visualizations that you have trouble reading because of your colorblindness?
Mostly I don’t bother reading them – there is no way to figure it out, even if I stare at it for an hour I’m not going to be able to see anything. How long would you look at a black and white print of a chart to figure out its color?
One thing that people misunderstand is that it doesn’t really matter what colorblindness you have. I’m greenblind, so I should be able to see for example orange ⬤ and purple ⬤ and grey ⬤, but that doesn’t help you much when you don’t know if what appears purple to you actually is purple ⬤, or some shade of turquoise ⬤. You don’t know when you’re not seeing something as you should, so you have to distrust the signal as a whole.
A big thanks to David, Wesley, Mark, Edurne’s friend, Graeme, Lee, Peter, Aaron, Rob and Kevin for sharing their experiences with us! It lets me think differently about colorblindness – I can imagine it better now – and I hope it helps you, too, dear reader. If you want to find out more about life as a colorblind person, I can recommend wearecolorblind.com. And if you haven’t seen them yet, consider reading part 1 and part 2 of this series on colorblindness.