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 (60, 62) disposed between polarisation filters (64, 66, 68) having substantially parallel polarisation directions, wherein each liquid crystal cell comprises a connector (80, 82) 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 (60, 62) 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 (60, 62) 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 (60, 62) disposed between polarisation filters (64, 66, 68) having substantially parallel polarisation directions, wherein each liquid crystal cell comprises a connector (80, 82) 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 (60, 62) 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 (60, 62) 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 (60, 62) 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 (60, 62) are substantially identical and rotated 180 degrees relative to each other.