A water-based ink includes a pigment, an amino acid having an alkylene group with three or more carbon atoms and having amino groups on a side chain thereof, a surfactant and/or a penetrating agent, and water. The surfactant includes an acetylene based surfactant. The penetrating agent includes an alkylene diol, a glycol ether compound, or both. An amount of the amino acid in the water-based ink relative to a total mass of the water-based ink is from 0.05 to 1 mass %. The amino acid is preferably arginine, lysine, or both. The water-based ink preferably further includes two or more wetting agents.

A water-based ink includes a pigment, an amino acid having an alkylene group with three or more carbon atoms and having amino groups on a side chain thereof, a surfactant and/or a penetrating agent, and water. The surfactant includes an acetylene based surfactant. The penetrating agent includes an alkylene diol, a glycol ether compound, or both. An amount of the amino acid in the water-based ink relative to a total mass of the water-based ink is from 0.05 to 1 mass %. The amino acid is preferably arginine, lysine, or both. The water-based ink preferably further includes two or more wetting agents.

An ink jet ink composition which is a water-based ink, includes a self-dispersible pigment, inorganic oxide particles, and a poly(ethylene glycol) represented by the following general formula (I), and the ink composition contains at least one type of metal ion selected from the group consisting of a potassium ion, a sodium ion, and a lithium ion.

HO—(CH.sub.2—CH.sub.2—O—).sub.n—H  (I)

In the above formula, n represents an integer of 3 to 9.

An ink jet ink composition which is a water-based ink, includes a self-dispersible pigment, inorganic oxide particles, and a poly(ethylene glycol) represented by the following general formula (I), and the ink composition contains at least one type of metal ion selected from the group consisting of a potassium ion, a sodium ion, and a lithium ion.

HO—(CH.sub.2—CH.sub.2—O—).sub.n—H  (I)

In the above formula, n represents an integer of 3 to 9.

A nanocarbon ink contains nanocarbons, a solvent, and a polyoxyethylene alkyl ether represented by the following expression: C.sub.nH.sub.2n(OCH.sub.2CH.sub.2).sub.mOH where, n=12 to 18 and m=20 to 100.

A nanocarbon ink contains nanocarbons, a solvent, and a polyoxyethylene alkyl ether represented by the following expression: C.sub.nH.sub.2n(OCH.sub.2CH.sub.2).sub.mOH where, n=12 to 18 and m=20 to 100.

The pretreatment liquid of the present invention is applicable for a fabric to be used for inkjet textile printing, and the pretreatment liquid contains a block copolymer including a hydrophobic block derived from a hydrophobic resin having an SP value of less than 11 and a hydrophilic block derived from a hydrophilic resin having an SP value of 11 or more, with the difference between the SP values of the hydrophobic resin and the hydrophilic resin of 1.0 or more; and water.

The pretreatment liquid of the present invention is applicable for a fabric to be used for inkjet textile printing, and the pretreatment liquid contains a block copolymer including a hydrophobic block derived from a hydrophobic resin having an SP value of less than 11 and a hydrophilic block derived from a hydrophilic resin having an SP value of 11 or more, with the difference between the SP values of the hydrophobic resin and the hydrophilic resin of 1.0 or more; and water.

An ink comprises (i) a carrier; (ii) graphene and/or graphene oxide particles dispersed in the carrier; and (iii) a viral active and/or anti-microbial component adhered to the graphene and/or graphene oxide particles.

An ink set includes an inkjet ink and a cleaning solution. The inkjet ink contains a first aqueous medium, a carbon black, a dispersing resin, a first zwitterionic surfactant having an amidoalkylbetaine structure, and a first sugar alcohol. The carbon black has an oil absorption number of at least 130 mL/100 g and no greater than 165 mL/100 g. A ratio of a content of the dispersing resin to a content of the carbon black is at least 12.0% by mass and no greater than 19.0% by mass. The cleaning solution contains a second aqueous medium, a second zwitterionic surfactant having an amidoalkylbetaine structure, and a second sugar alcohol.