The present invention provides (I) a method of manufacturing a triphenylmethane colorant that can suppress the sub-reactions in conversion to a sulfonamide and is industrially advantageous, (II) a colorant compound that has both excellent spectral characteristics and a high solubility relative to organic solvents or polymers as a coloring agent to be used in color filters and (III) a blue resist composition for use in a color filter that shows a high lightness and an excellent hue particularly for blue color and can be used to display an image that is excellent in terms of spectral characteristics and contrast.