Black and White
The absolute best way to ensure that a colorblind person can see an image or text correctly is to use black and white, along with shades of gray. This is the only way you can be sure that what you are seeing is what a colorblind person will see when he looks at it. Although black and white are not the most appealing colors from a design perspective, they could be used for the important information with other colors as accents that do not add much content.
Ensure that a colorblind person can read text by using a monochromatic color palette with a light shade for the background and a dark shade of the same color for the text, according to Digital Web Magazine. Try to choose shades with very different saturation, which is a measure of how high their contrast would be if the color pigments were removed. Any monochromatic palette is effective. For example, you could have a light purple background color and dark purple text on it, with a medium purple design around the edges. Although a colorblind person might not be able to identify which color you use, the individual should be able to read the text because the shades have enough contrast.
The vast majority of people who have trouble seeing color lack the ability to distinguish either the red pigment or the green pigment in colors. Less than 1 percent of colorblind people have trouble seeing blue, so blue is an ideal color to use when designing something for people who are colorblind. Although colorblind people might not see the shade of blue exactly as it appears for people who are not colorblind --- blue likely includes some red and green tones, too --- they should be able to identify it as blue. One thing to watch: Because blue is at the far end of the color spectrum, dark shades of blue might be difficult for colorblind people to distinguish from black.