A color filter using an organic pigment the primary particles of which have a mean particle diameter of 20 to 200 nm and a particle diameter distribution of within ± 35 nm, and which has a color difference of within 5 after exposure to illumination of at least 100,000 lux for at least 100 hours at a surface temperature of not lower than 50 °C; a color filter which has a transmission factor ratio (T485/T610) of up to 3.5 between a transmission factor (T485) of a green pigment film for a wavelength of 485 nm and a transmission factor (T610) for a wavelength of 610 nm, has a maximum transmission factor of the pigment film of at least 60 % and has a wavelength of the maximum transmission factor of 540 to 550 nm; and a color filter using specific organic pigments as pigments for red, green and blue. The color filters have high light fastness and heat resistance to withstand the use of a high illumination light source, and can be utilized for a liquid crystal projector, and so forth.