An automatic welding filter , comprising: a switchable filter that changes from a light transmission state to a dark transmission state in response to an activation signal; a colour-tunable filter, being in optical alignment with the switchable filter; and an electronic control unit for receiving and controlling the signals, wherein the colour-tunable filter comprises two liquid crystal cells disposed between polarisation filters having substantially parallel polarisation directions, wherein each liquid crystal cell comprises a connector for applying different voltages to the liquid crystal cell; characterized in that : the spectral transmittance of the colour-tunable filter is variable in response to a user-selected colour signal; and the liquid crystal cells are low twist liquid crystal cells each having a twist angle of 40 degrees, wherein the first low twist liquid crystal cell is disposed between a first polarisation filter and a second polarisation filter , the second low twist liquid crystal cell is disposed between the second polarisation filter and a third polarisation filter , the polarisation filters 64, 66, and 68 having differently oriented polarisation directions, 0 degrees, 5 degrees and 10 degrees, respectively, from a reference axis, and the first and second low twist liquid crystal cells are substantially identical and rotated 180 degrees relative to each other. a switchable filter that changes from a light transmission state to a dark transmission state in response to an activation signal; a colour-tunable filter, being in optical alignment with the switchable filter; and an electronic control unit for receiving and controlling the signals, wherein the colour-tunable filter comprises two liquid crystal cells disposed between polarisation filters having substantially parallel polarisation directions, wherein each liquid crystal cell comprises a connector for applying different voltages to the liquid crystal cell; characterized in that : the spectral transmittance of the colour-tunable filter is variable in response to a user-selected colour signal; and the liquid crystal cells are low twist liquid crystal cells each having a twist angle of 40 degrees, wherein the first low twist liquid crystal cell is disposed between a first polarisation filter and a second polarisation filter , the second low twist liquid crystal cell is disposed between the second polarisation filter and a third polarisation filter , the polarisation filters 64, 66, and 68 having differently oriented polarisation directions, 0 degrees, 5 degrees and 10 degrees, respectively, from a reference axis, and the first and second low twist liquid crystal cells are substantially identical and rotated 180 degrees relative to each other. the spectral transmittance of the colour-tunable filter is variable in response to a user-selected colour signal; and the liquid crystal cells are low twist liquid crystal cells each having a twist angle of 40 degrees, wherein the first low twist liquid crystal cell is disposed between a first polarisation filter and a second polarisation filter , the second low twist liquid crystal cell is disposed between the second polarisation filter and a third polarisation filter , the polarisation filters 64, 66, and 68 having differently oriented polarisation directions, 0 degrees, 5 degrees and 10 degrees, respectively, from a reference axis, and the first and second low twist liquid crystal cells are substantially identical and rotated 180 degrees relative to each other. <EOS>