Patent ID: 7083668

Claim:
An ink set comprising a plurality of inks different in hues, wherein the plurality of inks includes a yellow ink containing a coloring agent that is a dye represented by the following general formula (1), A−N=N−B (1) wherein A and B each independently represent a heterocyclic group which may be substituted, the dye having: a λmax of from 390 nm to 470 nm; an I(λmax+70 nm)/I(λmax) ratio of not greater than 0.4, in which I(λmax) is the absorbance at λmax and I(λmax+70 nm) is the absorbance at (λmax+70 nm); and a forced fading rate constant of not greater than 5.0×10 −2 [hour −1 ], in which the forced fading rate constant is decided by dissolving and/or dispersing the dye in an aqueous medium to form an ink composition for ink jet recording, printing the ink composition on a reflection type medium, thereafter measuring a reflection density through a Status A filter, specifying one point having a reflection density (DB) in an yellow region of 0.90 to 1.10 as an initial density of the ink, forcedly fading the printed matter by use of an ozone fading tester that can regularly generate 5 ppm of ozone, and determining the time taken until the reflection density reaches 80% of the initial density.