U.S. 8,147,608 B2
Sensient Colors LLC has been granted a patent for a method of modifying a pigment, the method is comprised of sulfonating a pigment comprised of at least one of an azo pigment, a phthalocyanine pigment, an anthraquinone pigment, a quinacridone pigment, a thioindigo pigment, a triphenylmethane lake pigment, an oxazine lake pigment and a carbon black comprised of an aggregate of carbon black particles; and subsequently oxidizing the pigment to produce a modified pigment.