The hex color #f5ef90 is a light color. The web-safe version is Hex
#FFFF99. A complementary color is
#0A106F. The grayscale version is
#D1D1D1. A 20% lighter version of the original color is
#FFFFC3, and Hex
#C2BC5D is the 20% darker color. If the color is saturated by 10%, you get
#F9F289. If the color is desaturated by 10%, the color
#F1EC97 is obtained.