Gradual lightening / blue black colour shift in a tattoo is called:
Changes in tattoo maturation Halo effect - extrusion of pigment on deposition near follicle Washing out / leaching/pigment migration-carrying away of pigment by macrophages on deep inseion Ref: Textbook of dermatosurgery & cosmetology, satish S savant, E-2,P-338.
Tyndall effect
Halo effect
Washing out
Leaching