What is Color Blindness?
Color blindness encompasses seven different types, which are grouped into three broad categories. These categories are helpful for understanding how someone else sees, which is often challenging for conventionally sighted people.
The first and most common category is red-green color blindness. With all of these, it can be challenging to tell the difference between red and green. Depending on the specifics, it may be impossible to tell at all! However, this often does not limit a person’s daily activities.
The four conditions that fall under red-green color blindness are:
- Deuteranomaly
- Protanomaly
- Protanopia
- Deuteranopia
The second category is blue-yellow color blindness, which is less common than red-green color blindness. This category actually affects numerous color combinations, such as telling the difference between blue and green.
The two conditions that fall in this category are:
- Tritanomaly
- Tritanopia
The third category is complete color blindness, sometimes called monochromacy or achromatopsia. This type of color blindness is very rare and can affect other aspects of vision measurement.
Typically, color blindness is inherited, but it can be acquired later in life as well. This is part of why many optical exams include color blindness tests, even for adults.
Referring to Color Blindness
Many people prefer person-first language when discussing their color blindness. Color blindness does affect the complete life experience; however, many people do not see it as defining their lives. However, you may still want to ask, as some do prefer something like colorblind person.
Creating an Accessible Environment for People with Color Blindness
Don’t Rely on Colors to Convey Important Information
Modern media relies heavily on graphics and videos, many of which depend on certain color schemes. Unfortunately, these schemes are often not designed for people with color blindness or any other visual difference.
While graphics are still an excellent option for recognizability, branding, and other purposes, relying solely on them to convey information is inadvisable. Instead, make sure any critical information is also available in the text of the same post.
If you do want to use colors that are friendly to people with color blindness, consider checking the proposed colors in a color blindness simulator. Additionally, avoid placing red and green, blue and yellow, or other common problematic combinations right next to each other.
Provide Image Descriptions and Alt Text
Image descriptions describe the purpose of the image, while alt text describes what’s in the image. Both are great tools for helping anyone who sees differently from the typical spectrum. Providing these tools is generally more broadly usable.
Keep Color Usage Practical
Color is a part of most media communication these days. Social media feeds are full of it to attract attention, colored flyers are normal for events, and even how stores do their decorations. However, these colors are often chosen for their appeal to conventional aesthetics, not accessibility.
Choosing color combinations with good contrast can help people who are color blind. For example, there’s a reason the default of most word-processing applications is black text on a white background. Try to avoid using colors that are close in shade.
Add Other Visual Cues
In some cases, color indicates the relative importance of something, such as a field on a form or a box on a website. In these cases, adding a visual indicator such as an asterisk next to required fields on a form or crosshatching to show which box is selected can be helpful.
Ensure Proper Lighting Contrast
As with many conditions, people with color blindness do benefit from proper lighting that enhances the contrast between colors in a space. When hosting an event, make sure the room is bright and well-lit.
Feel like this guide is missing something? Let us know at sfcoa@sfi.org.
Want to know more about accessible communication? Check out Accessible Communication 101.