Abstract: Described herein is magenta ink composition, comprising a pigment consisting of one or more quinacridone pigments; a resin; and a polymeric amine dispersant having a Total Base Number of at least 300 mg KOH/gram. Also described herein is a method of printing comprising applying the magenta ink composition to a substrate, and a printed substrate comprising the magenta ink composition.

Abstract: Described herein is a yellow liquid electrophotographic ink composition comprising: a thermoplastic resin comprising a polymer having acidic side groups; and a colorant comprising a yellow pigment, wherein the yellow pigment comprises a hydrazone compound. Also described herein is a method of producing a printed substrate using the yellow liquid electrophotographic ink composition and a printed substrate produced therefrom.

Abstract: In an example of a printing system, the amount of a printing fluid that is transferred from a developer unit onto an imaging plate is varied in order to alter the optical density of an area covered by the printing fluid.

Abstract: In an example of a printing system, the amount of a printing fluid that is transferred from a developer unit onto an imaging plate is varied in order to alter the optical density of an area covered by the printing fluid.

Abstract: A set of screens is provided for use in printing respective color separations in a halftone color printing process. This set of screens comprises at least two clustered-dot screens and the frequency and angle parameter values of the screens is such that the lowest frequency moiré produced by any combination of at least two frequency components, taken from the group comprising the first and second screen harmonics, for which the sum of the harmonic orders of the frequency components in the combination is less than a predetermined value, is of a sufficiently high frequency as to be substantially unperceivable to the human visual system; other moirés are also substantially unperceivable to the human visual system. The lowest frequency moiré serves to reduce the visibility of color changes caused by color plane registration variations. A printing system and method employing the screen set are also provided.

Abstract: A set of screens is provided for use in printing respective color separations in a halftone color printing process. This set of screens comprises at least two clustered-dot screens and the frequency and angle parameter values of the screens is such that the lowest frequency moiré produced by any combination of at least two frequency components, taken from the group comprising the first and second screen harmonics, for which the sum of the harmonic orders of the frequency components in the combination is less than a predetermined value, is of a sufficiently high frequency as to be substantially unperceivable to the human visual system; other moirés are also substantially unperceivable to the human visual system. The lowest frequency moiré serves to reduce the visibility of color changes caused by color plane registration variations. A printing system and method employing the screen set are also provided.