Color Blind

Overview

Color-blindness does not literally mean that a person can’t see any color at all (except in very rare cases). Color-blindness refers to the inability to distinguish between certain kinds of colors, especially colors that are of equal brightness or luminosity, even if the colors themselves appear quite different to people without color-blindness.

Types of Color-Blindness

There are several kinds of color-blindness, and varying degrees within those types, so it is difficult to provide a precise explanation of which color combinations are the worst for people who experience color-blindness. The most prevalent form of color-blindness, though, is red-green color-blindness. Deuteranopia and Protanopia are two common sub-types of red-green color-blindness. Some people may also have what is known as Tritanopia, or blue-yellow color-blindness. Though very rare, there are those who inherit an insensitivity to all colors. People who have Achromatopsia see colors in grayscale.

Though is it difficult to truly capture how people experience color-blindness, the tabs below simulate how a person with red-green color-blindness and grayscale vision may see colors according to the characteristics of these conditions.

Red and Green Colorblindness and Achromacy

Red and Green Colors

The most common form of color-blindness is red-green color-blindness, which makes it hard to distinguish between reds, oranges, and greens. Shown above are a few examples of the types of colors that can be easily confused.

Red/Green Color Blindness

Those who have red-green color-blindness may see the images in the manner they have been adjusted here. The numbers are very difficult to distinguish this way.

All Colors

In very rare cases, a person’s vision can be insensitive to all colors, rendering the world in a type of grayscale. Here are the same images from the previous examples, modified to appear in grayscale.

Red and Black Colorblindness

In addition to red-green and blue-yellow color-blindness, the colors red and black may be difficult to distinguish for some people.

Red and Black Colors

Red and black can be difficult to distinguish for some people. Here is how red and black may appear to those who may not be colorblind.

Red and Black Simulation

Now, here is how that same image may appear to those who have trouble seeing red and black. The red text and the red image nearly blend together with the black background.

Assistive Technologies for People with Colorblindness

There aren’t many assistive technologies for people with color-blindness. For the most part, it is a condition that people just have to live with. A company called EnChroma claims to have developed glasses that can help compensate for some kinds of color-blindness. https://enchroma.com/. Their products may be worth checking out if you experience color-blindness.

Web Accessibility for People with Colorblindness

The majority of people who are colorblind are able to see colors, but there are certain colors and color combinations that may be difficult for them to differentiate. It is critical not to rely on color alone to communicate information. To learn more about color-blindness, explore the resources below.

Related Links: Color-Blindness

• Article: Color Blindness or Color Vision Deficiency (Color Blindness Tests and Facts) by Gianni A. Sarcone (Archimedes Laboratory Project)
• Article: Color blindness (Wikipedia)
• Simulator: NoCoffee vision simulator (for Firefox only)
• Simulator: Color Oracle: Design for Color Impaired (free download for Windows, Mac, and Linux)

Design Considerations for Colorblindness