The hex color #a40f0f is a dark color. The web-safe version is Hex
#990000. A complementary color is
#5BF0F0. The grayscale version is
#414141. A 20% lighter version of the original color is
#D74242, and Hex
#710000 is the 20% darker color. If the color is saturated by 10%, you get
#AE0A0A. If the color is desaturated by 10%, the color
#9A1414 is obtained.