Screenshot of ColorBlindSim website with logo and text

Color Blindness Simulator

Interested in understanding or sharing about color blindness?

‘Color blind’ is defined as the partial or total inability to distinguish one or more chromatic colors. According to the Color Blind Awareness website, color blindness affects approximately 1 in 12 men (8%) and 1 in 200 women. Learn more about color blindness here.

As Teachers of the Visually Impaired and Orientation & Mobility Specialists, we work with students who have a range of color blindness. In the classroom, color is often critical to understanding information or completing assignments. Think about the kindergarten worksheets that ask the student to circle the red items or color the squares green. Older students may be asked to analyze charts and graphs that are color coded. O&M students may be expected to use color landmarks when traveling a route. Functionally, students are expected to wear matching socks and color-coordinated clothing.

Mainstream classroom teachers (and family members!) should understand an individual’s specific type of color blindness and before figuring out how to accommodate for this. When explaining color blindness, ‘a picture is worth a thousand words’ is the great approach!  ColorBlindSim is a great color blind simulator that can be used to demonstrate what your student’s type of color blindness.  This is a great activity to share during an IEP meeting or when working when talking about accommodations with classroom teachers! 

Color Blind Simulation Activity

Use a colorful worksheet, website page or book page that is currently being used in your student’s classroom – ideally, one that requires the ability to distinguish colors accurately in order to successfully complete the worksheet! Open the ColorBlindSim website on your tablet or smart phone. (You must allow the website to access your camera.) Focus the camera on the worksheet. Open the menu in the top left corner of the screen and select the desired type of color blindness.  The options are:

Once you select your desired color blindness type, you can use the camera and view the worksheet (or other items in the environment) live or you can take a picture of the desired worksheet and switch through the color blindness options while viewing exact same image.

The first image below shows a spring day with vivid green grass using the Normal Vision mode. The second image below shows the same scene with Deuteranopia (green-blindness) where the grass is brown.

Screenshot of ColorBlindSim website; image of a spring day with bright green grass, flowering trees and pond in the Normal Vision mode. Screenshot of ColorBlindSim website; image of a spring day with brown grass; pond, trees and sky are various shades of brown, black and white. Scene is in the Deuteranopia (green blindness) mode.

By Diane Brauner

Color drawing of a digital camera with some photos in the back representing images needing alt text.

How to Write Alt Text and Image Descriptions for the visually impaired


Creating Tactile Graphics Images Part 7: Color the Picture Worksheet

Using Twitter with Vision Impairment.

Twitter accessibility features for low vision