Not all individuals see colors the same. Over 7% of the U.S. population has a type of color vision disability. Some may not be able to see certain colors, or may have a hard time differentiating between various colors. Make your content accessible by following accessible design practices for color contrast and color.
Examples of contrast can be seen in Figure 1. Most would have trouble reading the first line, however the same light foreground color with a black background is easy to read.

Test color contrast using WebAim's Contrast Checker. Follow the steps below, or watch the video for an example.
This quick video will walk you through the steps of checking for accessible color contrast using WebAIM’s Color Contrast Checker tool.
Color values most commonly follow 3 models, each based on medium (digital or print) and how colors are mixed and presented:
The process of finding color value will vary by program, however typically you can highlight the text or item, click on the program's color option, and locate the color value.
In Microsoft programs, you can find the RGB color value by highlighting the item, selecting the color drop-down from the "Format" tab, selecting “More Colors,” and clicking the “Custom” tab.
If color is used to communicate information visually, do one or more of the following:
Use color AND text to convey the information.

Use color AND varying patterns to convey the information.

Use color AND other labeling methods such as symbols to convey the information.

Take this quick, 4-question quiz to see how much you can recall about best practices for ensuring accessibility with color! Note, this quiz is just for fun and is 100% anonymous.