The hex color #664f1c is a dark color. The web-safe version is Hex
#666633. A complementary color is
#99B0E3. The grayscale version is
#464646. A 20% lighter version of the original color is
#99824F, and Hex
#331C00 is the 20% darker color. If the color is saturated by 10%, you get
#695018. If the color is desaturated by 10%, the color
#634E20 is obtained.