Abstract: A water-based ink includes: a dye; water; an acidic preservative; and at least one of a surfactant and a penetrant. The acidic preservative preferably includes at least one selected from the group consisting of a polyvalent unsaturated fatty acid, a polyvalent unsaturated fatty acid salt, dehydroacetic acid, and a dehydroacetate. A content of the acidic preservative in the water-based ink is preferably 0.3% by mass to 6.0% by mass relative to a total mass of the water-based ink. The surfactant preferably includes an acetylene-based surfactant. The penetrant preferably includes at least one selected from the group consisting of an alkylene diol and a glycol ether compound.

Abstract: A water-based ink for inkjet recording, includes: a pigment; water; and an acidic preservative. The pigment is preferably a self-dispersing pigment. The acidic preservative preferably includes at least one selected from the group consisting of a polyvalent unsaturated fatty acid, a polyvalent unsaturated fatty acid salt, dehydroacetic acid, and a dehydroacetate. A content of the acidic preservative in the water-based ink is preferably 0.5% by mass to 5.0% by mass relative to a total mass of the water-based ink. The water-based ink preferably further includes a surfactant. The water-based ink preferably further includes a penetrant which includes at least one selected from the group consisting of 1,2-hexanediol, 3-methyl-1,5-pentanediol, and triethylene glycol-n-butyl ether (BTG).

Abstract: A water-based ink for ink-jet recording includes: a solid solution of a quinacridone pigment including C.I. Pigment Red 202 and C.I. Pigment Violet 19; an azo pigment including C.I. Pigment Red 48:3; and water.

Abstract: A water-based ink for ink-jet recording, includes: a solid solution of a quinacridone pigment including C.I. Pigment Violet 19 and C.I. Pigment Red 122, an azo pigment including C.I. Pigment Red 48:3, and water.