A water-based ink of the present invention comprises water, a plurality of
different water-soluble organic solvents, and a water-insoluble coloring
material, wherein the above water-soluble organic solvents consist of a
good solvent to the above water-insoluble coloring material and a poor
solvent to the above water-insoluble coloring material, and the total
amount (% by mass) of the good solvents in the ink is represented by A
and the total amount (% by mass) of the poor solvent in the ink is
represented by B, the ratio of A to B ranges from 10:5 to 10:30 both
inclusive, and when the respective Ka values of the above water-soluble
organic solvents are determined by the Bristow method and compared with
each other, a water-soluble organic solvent having the largest Ka value
is the poor solvent. The pigment ink has a sufficiently large area factor
even with a small amount of ink and provides an image of high OD.