The hex color #b31d0c is a dark color. The web-safe version is Hex
#CC3300. A complementary color is
#4CE2F3. The grayscale version is
#494949. A 20% lighter version of the original color is
#E6503F, and Hex
#800000 is the 20% darker color. If the color is saturated by 10%, you get
#BE1906. If the color is desaturated by 10%, the color
#A82112 is obtained.