abstract |
(57) A near-infrared ray characterized in that at least one naphthalocyanine pigment of a naphthalocyanine pigment is pulverized to an average particle size of 0.5 μm or less and dispersed in an ink medium. Absorbing ink. The present invention provides a near-infrared absorbing ink having high durability, a printing method and printed matter using the same, and a method for detecting the obtained printed matter in a simple manner. It can be applied to ink and is extremely valuable in practical use. |