The hoya 67mm hmc green x1 filter transmits a relatively narrow wavelength band centred around light in the green spectrum and is named after the wavelength at which their transmittance attains the maximum value when desiring to attain the maximum transmittance at a specific wavelength or to absorb light of shorter wavelengths bonding these filters and sharp cut filters together will serve the purpose green filters are used as contrast effect filters for black and white photography and also