Provided are a resin composition including a pigment, a compound A which includes 3 or more basic groups in one molecule, has an amine value of 2.7 mmol/g or more, and has a molecular weight of 100 or more, and a resin having an acid group, in which the pigment is included in an amount of 40% by mass or more in a total solid content of the resin composition; a film formed of the resin composition; and an optical filter, a solid-state imaging element, and an image display device, which include the film.

An azo iron complex dye which does not contain harmful heavy metals, exhibits sufficient solubility in organic solvents for practical use, and exhibits an excellent black color. The azo iron complex dye contains a disazo-monoazo iron complex represented by the following chemical formula (1)

##STR00001## (in the chemical formula (1), R.sup.1 and R.sup.2 are each independently a straight or branched alkyl group having 3-10 carbon atoms, R.sup.3 is an electron-withdrawing group, R.sup.4 is a straight or branched alkyl group having 1-5 carbon atoms or a straight or branched alkoxy group having 1-5 carbon atoms, R.sup.5 is a nitro group, a sulfonamide group or a halogen atom, R.sup.6 is a hydrogen atom, a straight or branched alkyl group having 1-8 carbon atoms, a nitro group or a halogen atom, R.sup.7 is a hydrogen atom or a straight or branched alkyl group having 3-12 carbon atoms, and A.sup.+ is a monovalent cation).

An azo iron complex dye which does not contain harmful heavy metals, exhibits sufficient solubility in organic solvents for practical use, and exhibits an excellent black color. The azo iron complex dye contains a disazo-monoazo iron complex represented by the following chemical formula (1)

##STR00001## (in the chemical formula (1), R.sup.1 and R.sup.2 are each independently a straight or branched alkyl group having 3-10 carbon atoms, R.sup.3 is an electron-withdrawing group, R.sup.4 is a straight or branched alkyl group having 1-5 carbon atoms or a straight or branched alkoxy group having 1-5 carbon atoms, R.sup.5 is a nitro group, a sulfonamide group or a halogen atom, R.sup.6 is a hydrogen atom, a straight or branched alkyl group having 1-8 carbon atoms, a nitro group or a halogen atom, R.sup.7 is a hydrogen atom or a straight or branched alkyl group having 3-12 carbon atoms, and A.sup.+ is a monovalent cation).

An azo iron complex dye which does not contain harmful heavy metals, exhibits sufficient solubility in organic solvents for practical use, and exhibits an excellent black color. The azo iron complex dye contains a disazo-monoazo iron complex represented by the following chemical formula (1) ##STR00001##
(in the chemical formula (1), R.sup.1 and R.sup.2 are each independently a straight or branched alkyl group having 3-10 carbon atoms, R.sup.3 is an electron-withdrawing group, R.sup.4 is a straight or branched alkyl group having 1-5 carbon atoms or a straight or branched alkoxy group having 1-5 carbon atoms, R.sup.5 is a nitro group, a sulfonamide group or a halogen atom, R.sup.6 is a hydrogen atom, a straight or branched alkyl group having 1-8 carbon atoms, a nitro group or a halogen atom, R.sup.7 is a hydrogen atom or a straight or branched alkyl group having 3-12 carbon atoms, and A.sup.+ is a monovalent cation).

An azo iron complex dye which does not contain harmful heavy metals, exhibits sufficient solubility in organic solvents for practical use, and exhibits an excellent black color. The azo iron complex dye contains a disazo-monoazo iron complex represented by the following chemical formula (1) ##STR00001##
(in the chemical formula (1), R.sup.1 and R.sup.2 are each independently a straight or branched alkyl group having 3-10 carbon atoms, R.sup.3 is an electron-withdrawing group, R.sup.4 is a straight or branched alkyl group having 1-5 carbon atoms or a straight or branched alkoxy group having 1-5 carbon atoms, R.sup.5 is a nitro group, a sulfonamide group or a halogen atom, R.sup.6 is a hydrogen atom, a straight or branched alkyl group having 1-8 carbon atoms, a nitro group or a halogen atom, R.sup.7 is a hydrogen atom or a straight or branched alkyl group having 3-12 carbon atoms, and A.sup.+ is a monovalent cation).