Galvoptics' photopic filters transmit from the optical wavelengths range above 200nm. Photopic eye response filters pass wavelengths of light in proportion to the eyes' natural response. When used in combination with a broadband source and detector, the transmission is very similar to the human eye spectral response.
The human eye uses cones to sense light in three bands of colour. The pigments of the cones have maximum absorption values at wavelengths of 420 nm (blue), 534 nm (blue-green), and 564 nm (yellow-green).