Radiation curable ink jet composition and ink jet method

A radiation curable ink jet composition comprising:

• polymerizable compounds;
• at least one photopolymerization initiator;
• 2,2,6,6-tetramethylpiperidinyl-1-oxyl or a derivative thereof;
• and
• a fluorescent whitener,
• wherein the fluorescent whitener is at least one selected from the group consisting of a naphthalene benzoxazolyl derivative, a thiophene benzoxazolyl derivative, a stilbene benzoxazolyl derivative, a coumarin derivative, a styrene biphenyl derivative, a pyrazolone derivative, a stilbene derivative, a styryl derivative of benzene and biphenyl, a bis(benzazole-2-yl) derivative, carbostyril, naphthalimide, a derivative of dibenzothiophene-5,5′-dioxide, a pyrene derivative, or pyridotriazole,
• the polymerizable compounds include a vinyl ether group-containing (meth)acrylate represented by the following general formula (I),
• a content of the vinyl ether group-containing (meth)acrylate with respect to a total mass of the radiation curable ink jet composition is 15 percent by mass or more, and
• the at least one photopolymerization initiator includes ethyl (2,4,6-trimethylbenzoyl)phenylphosphinate, an amount of the ethyl (2,4,6-trimethylbenzoyl)phenylphosphinate being 30 to 60% by mass relative to a total amount of the at least one photopolymerization initiator contained in the radiation curable ink jet composition,
• H2C═CR1—CO—OR2—O—CH═CH—R3 (I)
• where in the formula, R1 represents a hydrogen atom or a methyl group, R2 represents a divalent organic residue having 2 to 20 carbon atoms, and R3 represents a hydrogen atom or a monovalent organic residue having 1 to 11 carbon atoms.