| abstract |
This invention relates to an aqueous solution composition (aqueous ink composition) and a novel naphthalocyanine pigment, the aqueous solution composition containing a water soluble naphthalocyanine pigment represented by the following formula (1) or its salt, these compounds having a high absorption at near infrared region, so being useful as an near infrared absorbent, and the aqueous solution having excellent storage stability, so being useful as an near infrared absorbing aqueous ink. (wherein, M represents hydrogen atom, metal atom, metal oxide, metal hydroxide or metal halide, X represents a carbonyl group or a sulfonyl group, W1 to W4 individually represents hydrogen atom or an ionic hydrophilic group etc. , at least one of the W1 to W4 is a group other than hydrogen atom, n represents an integer of 1 to 24. ) |