PURPOSE: To enable manufacturing of a printed matter which is rich in gradation, by a method wherein printing is performed by a printing ink obtained by compounding a pigment and organic pigment having functional characteristics of a micro-capsule or a mica titanium pigment as a vehicle.

CONSTITUTION: A printing mechanism is constituted of an impression cylinder 1, printing plate 2, printing plate cylinder 3, anilox roller 4, doctor blade 5, fountain roller 6 and ink pan 7. Printing ink prepared by compounding a pigment and organic pigment or a mixture having functional characteristics of a micro-capsule or a mica titanium pigment or a fluorescent pigment as a vehicle is used as printing ink 8 to be used for the printing mechanism. A pattern or a letter constituted of dots, line drawing and solid is printed on wet paper 9 on a paper making machine which is under state where a large quantity of water is contained with the foregoing printing ink 8. The obtained printed matter is free from generation of blur or a marginal zone and quite favorable one. Then paper useful for prevention of copying or foregery is obtained.