One thing Gikon forgot to mention is that there are 2 different places to color-shift in.
The first place is in the Item datablock, and the second place is in the WeaponImage datablock.
In the Item DB, the color-shift only affects the pick-up-able item and its inventory picture.
The WeaponImage DB, however, affects the actual item that you hold. It also usually piggy-backs on the Item's colorshift, as Gikon was showing you.