Thank you for reaching out!
Color-blindness, also known as Color Vision Deficiency (CVD), is the inability to distinguish certain shades of color. (American Optometric Association) There are 6 defined types of color vision deficiency and the condition is usually genetic (National Eye Institute).
When you are using Esri software, there are a variety of ways that you can test your content to make sure you are choosing colors that will provide enough contrast for someone with CVD.
- Colorblindly is a Chrome extension that simulates colorblindness
- ColorBrewer allows you to select colors for color ramps to test their contrast specifically for cartography
- WebAIM Contrast Checker can tell you whether colors provide enough contrast, which is also important to people with low vision.
I also found a few blogs that have been published over the years through ArcNews, etc. that might be interesting:
ArcNews - To See or Not to See
ArcGIS Living Atlas - Red... Green... What?
ArcWatch - Ramp Up Your Mapping
This article from SiteImprove also provides a great summary on website accessibility standards that are applicable to those with a visual impairment such as color vision deficiency.
I'm sure there is more information out there just a google search away, so I hope others will pass along additional useful information here too!
