The forgery-preventing film of printing ink printed matter and

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PROBLEM TO BE SOLVED : To provide an anti-counterfeit ink excellent in weather resistance, which transmits a visible light region and shows absorption in a near-infrared region.SOLUTION : The anti-counterfeit ink is prepared by dispersing an anti-counterfeit ink composition containing a near-infrared absorbing material in a solvent. The near-infrared absorbing material comprises one of a composite tungsten oxide represented by MyWOz (where M represents at least one element selected from H, He, alkali metals, alkaline earth metals, rare earth elements, Mg, Zr, Cr, Mn, Fe, Ru, Co, Rh, Ir, Ni, Pd, Pt, Cu, Ag, Au, Zn, Cd, Al, Ga, In, Tl, Si, Ge, Sn, Pb, Sb, B, F, P, S, Se, Br, Te, Ti, Nb, V, Mo, Ta, Re, Be, Hf, Os, Bi, and I; and y and z satisfy 0.001≤y≤1 and 2.2≤z≤3.0) and a Magneli phase represented by WyOz (where y and z satisfy 2.45≤z/y≤2.999), and has a particle diameter of 800 nm or less. The anti-counterfeit ink is transparent in a visible light region.