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 176; and water.

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 202, an azo pigment including C.I. Pigment Red 150, and water.

A water-based ink for ink-jet recording includes: a solid solution of a quinacridone pigment including C.I. Pigment Red 122 and C.I. Pigment Violet 19; an azo pigment including C.I. Pigment Red 146; and water. Mass ratio (Q:A) of a content amount (Q) of the solid solution of the quinacridone pigment to a content amount (A) of the azo pigment in an entire amount of the water-based ink is in a range of 9:1 to 1:9.

The present invention provides a pigment dispersant: that is capable of remarkably ameliorating fluidity of a liquid product, such as an ink or a paint, which contains particles of a pigment, such as a black azo pigment, in a dispersed state; that can suppress aggregation of piment particles; that prevents occurrence of foreign substances; and that is capable of producing a colored article excellent in optical density. Provided is a pigment dispersant being a compound represented by the following formula (1).

##STR00001##

wherein R.sub.1 and R.sub.2 each independently represent a group obtained by eliminating one hydrogen atom from an amino group of an amine compound containing a basic nitrogen atom, and R.sub.3 and R.sub.4 each independently represent a hydrogen atom, a halogen atom, an alkyl group, an alkoxy group, or a hydroxy group.

A yellow toner which provides, even in small amounts, a sharper color and brighter gloss, and higher reflection density than ever before, and which has excellent light resistance. The yellow toner contains a binder resin and a yellow colorant, wherein, as the yellow colorant, at least one of the compound A represented by the following general formula (1) and the compound B represented by the following general formula (2), and the compound C represented by the following formula (3) are contained:

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An optical film, a polarizing plate including the same, and a liquid crystal display including the same are provided. The optical film includes a protective layer and a contrast improving layer, wherein the contrast improving layer includes a second resin layer that is stacked from the protective layer, and a first resin layer facing the second resin layer.

The present invention relates to [1] a process for producing a pigment composition, including the step of subjecting a raw material pigment composition containing PY74 and a specific by-product to a treatment with an oxidizing agent, in which a content of the specific by-product in the pigment composition after the treatment on the basis of a content of PY74 in the pigment composition after the treatment is not more than 1,200 mg/kg; [2] a process for producing a pigment composition, including the step of subjecting a raw material pigment composition containing PY74, a specific by-product and water to a treatment with hydrogen peroxide; [3] a method of reducing a content of a specific by-product in a raw material pigment composition containing PY74 and the specific by-product, said method including the step of subjecting the raw material pigment composition to a treatment with an oxidizing agent; and [4] a method of preventing an ink for ink-jet printing from suffering from ejection defects, including the step of compounding the pigment composition produced by any of the aforementioned processes in the ink for ink-jet printing.

An ink set includes a first ink containing the compound represented by formula (y-1) or its salt, a second ink containing one or two or more of the compound represented by formula (m-1) or its salt, the compound represented by formula (m-2) or its salt, a compound represented by formula (m-3) or its salt, and the compound represented by formula (m-4) or its salt, and a third ink containing one or two or more of a compound represented by formula (c-1) or its salt, the compound represented by formula (c-2) or its salt, the compound represented by formula (c-3) or its salt, a compound represented by formula (c-4) or its salt, and the compound represented by formula (c-5) or its salt.

##STR00001##

A method for determining hydration of a polymer includes mixing a water-soluble, powdered dye with a powdered polymer and introducing the mixed water-soluble, powdered dye and powdered polymer into a water-based fluid. Full hydration of the powdered polymer is determined when the mixed water-soluble, powdered dye, powdered polymer and water-based fluid comprises substantially no internal optical contrast.

The present invention is directed to dye mixtures comprising dye(s) of formula (1)

##STR00001##

and specific other dyes, the process for the production of these mixtures as well as their use for dyeing textiles.