The present invention can provide a novel pigment useful in color image displays to form blue pixels capable of providing high-level brightness and saturation, especially a finely-divided pigment which has a bright hue and is excellent in pigment physical properties such as light fastness, solvent resistance and heat resistance, a process for producing the same, a pigment dispersion making use ofthe pigment, and an ink for color filters. The novel pigment is produced by forming into a pigment a subphthalocyanine represented by the following formula (1): wherein X is a halogen atom, presents diffraction peaks at diffraction angles (2 theta) of at least 7.0 DEG , 12.3 DEG , 20.4 DEG and 23.4 DEG in x-ray diffraction, and has an average particle size of 120 to 20 nm.