The hex color #b51b08 is a dark color. The web-safe version is Hex
#CC3300. A complementary color is
#4AE4F7. The grayscale version is
#484848. A 20% lighter version of the original color is
#E84E3B, and Hex
#820000 is the 20% darker color. If the color is saturated by 10%, you get
#C01702. If the color is desaturated by 10%, the color
#AA200E is obtained.