The hex color #b6211c is a dark color. The web-safe version is Hex
#CC3333. A complementary color is
#49DEE3. The grayscale version is
#515151. A 20% lighter version of the original color is
#E9544F, and Hex
#830000 is the 20% darker color. If the color is saturated by 10%, you get
#C01C17. If the color is desaturated by 10%, the color
#AC2621 is obtained.