An ink set comprising: at least two kinds of inks, each of the at least two kinds of inks having a common hue and different densities, and containing an aqueous medium and a dye, wherein each of the at least two kinds of inks has a corresponding discoloration velocity constant (k) for an image printed with each one of the at least two kinds of inks, and a ratio defined by a minimum value (k.sub.min) selected from among said corresponding constants divided by a maximum value (k.sub.max) selected from among the corresponding constants, is within a range of 0.7 to 1.0.