Ink comprising a compound of Formula (1) and salts thereof: Formula (1) wherein: Pc represents a phthalocyanine nucleus of Formula (2); Formula (2) x is greater than 0 and less than 1.8; y and z are both greater than 0; and the sum of (x+y+z) is 2.4 to 4.5: and a liquid medium. Also an ink-jet printing process, a material printed with an ink of the invention and an ink jet printing cartridge containing an ink of the invention ##STR00001##