The (often referred to in modern CS titles as the "Fade") is a popular custom model for Counter-Strike 1.6
w_knife.mdl (The model seen when the knife is on the ground). skeleton knife gradient for cs 16
Popular gradient styles:
A pro gradient leaves the handle (usually wrapped in paracord) completely desaturated. If your handle changes color with the blade, the modder messed up the UV mapping. The (often referred to in modern CS titles