Method for increasing color-fastness of organic coloring matter

A method for increasing fastness of an organic coloring matter, making coexist the organic coloring matter having the absorption maximum within the wavelength region from 400 nm to 700 nm with a compound represented by the following general formula in a medium:

• ##STR256## wherein R.sub.1 and R.sub.1 ' are independently selected from a hydrogen atom, an alkyl group, a cycloalkyl group, a halogen atom, an alkoxy group, an aryloxy group, --CO--O--R.sub.4, ##STR257## --NHCOR.sub.9 and --NHSO.sub.2 R.sub.13, R.sub.4 is selected from an alkyl group and a cycloalkyl group,
• R.sub.5 and R.sub.6 are independently selected from a hydrogen atom, an alkyl group, an aryl group and a cycloalkyl group, and R.sub.5 and R.sub.6 may be bonded to form a five to seven membered ring,
• R.sub.7 and R.sub.8 are the same as R.sub.5 and R.sub.6, R.sub.9 is selected from an alkyl group, an aryl group --OR.sub.10 and ##STR258## R.sub.10 is selected from an alkyl group and a cycloalkyl group, R.sub.11 and R.sub.12 are the same as R.sub.5 and R.sub.6, R.sub.13 is selected from an alkyl group, an aryl group and ##STR259## R.sub.14 and R.sub.15 are the same as R.sub.5 and R.sub.6, R.sub.2 and R.sub.2 ' are independently selected from a hydrogen atom, a halogen atom, an alkyl group, an alkoxy group, an alkoxycarbonyl group, an alkenyl group and a cycloalkyl group, and R.sub.1 and R.sub.2, or R.sub.1 ' and R.sub.2 ' may be bonded to form a condensed benzene ring, respectively,
• M is a metal atom,
• X and X' is independently selected from an oxygen atom and a sulfur atom,
• Y is selected from an oxygen atom, a sulfur atom, --SO and --SO.sub.2, and
• R.sub.3 is selected from a hydrogen atom, an alkyl group, an aryl group, a cycloalkyl group, --CO--R.sub.16, ##STR260## --SO--R.sub.21 and --SO.sub.2 R.sub.22, R.sub.16 is selected from an alkyl group, an alkenyl group, an aryl group and a cycloalkyl group, Z is a group of atoms necessary to complete five or six membered heterocyclic ring, R.sub.17 and R.sub.18 are independently selected from a hydrogen atom, an alkyl group, an aryl group and a cycloalkyl group, R.sub.17 and R.sub.18 may be bonded to form a five to seven membered ring, R.sub.19 and R.sub.20 are the same as R.sub.17 and R.sub.18, R.sub.21 is selected from an alkyl group and an aryl group and R.sub.22 is the same as R.sub.21.