![]() ![]() Off all of the things I’ve tested on him, the combination of colors on the image below (left) was the hardest for him to distinguish. My brother-in-law has CVD, so he is frequently the guinea pig for my color experiments. Not only are red, green, and brown problematic but so are blue and purple, pink and gray, and gray and brown. Below is the Tableau 10 color palette using a deuteranope simulation. Also, pink and gray together and gray and brown together can be problematic. If someone has issues with red, then the person may also have issues with purple, which would appear to look like blue. In an RGB color model, purple is achieved by using blue and red together. One color combination that is frequently overlooked is using blue and purple together. When colors are mixed, they can also be problematic. Since red, green, and orange all appear to be brown for someone with strong CVD, it would be more accurate to say, “Don't use red/green/brown/orange together.” However, it doesn’t end there. Notice that the problem here is much more complex than just simply red vs. With all the talk of stoplight colors and the nicknames for the CVD conditions, it’s no wonder that the data visualization rule has simply become “don’t use red and green.” Below is a simulation of Tableau’s stoplight colors using protanope simulation. ![]() Many data visualization tools have a “stoplight” palette built into them, and there are many companies (and clients and bosses) that still insist on using the stoplight palette. Be aware that it’s not just red and green While this may not be the best choice of colors, someone with CVD can interpret this chart without the use of color to make the comparison. Color is a secondary feature simply encoding positive vs. The chart below offers one example where it’s easy to see from the axis line that most numbers are positive and others are negative. If they stand alone-for example, two different charts, one red and one green-and they are labeled well, then it may not be an issue at all if they both appear brown in color. I’ve seen critiques regarding the use of red and green together in the same visualization, but the colors weren’t being used in a way that required someone to tell the difference between them. Using deuteranope simulation, we can see how difficult this would be. For example, in the chart below, color is needed to tell a good square from a bad square. Keep in mind that being able to tell these colors apart is only an issue if color is the only encoding method used to make a distinct comparison-for example, a good number vs. However, this can still be problematic when the colors are weak or blended together. People with weak CVD can see strong red and green colors as red and green. ![]() People with strong CVD (strong meaning a more severe condition of CVD) would see both red and green as brown. So indeed, using red and green together is a common problem. Red and green together can be problematic, but they can sometimes be used together These conditions are also commonly referred to as “red weak” and “green weak” or “red-green colorblindness.” (Note: I will not discuss blue/yellow CVD because it is far less common.) Here are some tips for designing vizzes that are colorblind-friendly. The two most common types of CVD are deuteranomaly and deuteranopia, which together count for about 6% of men, and protanomaly and protanopia, which account for another 2% (more information available at ). For the more common person with CVD, the key problem is that colors most people see as different will look the same. Having CVD does not mean that a person can’t see color unless you are the very rare person (one in 33,000 people) with achromatopsia. This is more commonly referred to as colorblindness, although colorblindness is not the most accurate term. The data-viz rule: “Don’t use red & green together.” The issue: "Ten percent of men are colorblind and mostly red/green issues." Reaction: "Don't use red and green together." Studies have shown that around 8% of men and 0.5% of women have color vision deficiency (CVD). For the first in the series, I examined the issue of using red and green together. I wanted to examine a few of them to better understand how they should be applied. This is a blog in a series of posts about some of the well-known “data-viz rules." We often hear these rules, but the details behind them are often not examined in depth or overlooked completely. This blog is part of a collection by Tableau Visionaries-the Tableau community's most distinguished leaders who inspire others by sharing their mastery, teaching, and collaborating. Reference Materials Toggle sub-navigation.Teams and Organizations Toggle sub-navigation.Plans and Pricing Toggle sub-navigation.
0 Comments
Leave a Reply. |
Details
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |