A liquid crystal display based projection system comprising: a light source; a polarization beam splitter arranged to receive light from the light source and to transmit a first linearly polarized light having a first linearly polarized light (241, 242) having a linear polarization axis corresponding to the X-axis of a right handed XYZ coordinate system with orthogonal axes; a reflective liquid crystal display panel arranged to optically modulate the first linearly polarized light, the liquid crystal display panel having a slow-axis and a fast-axis; the polarization beam splitter being arranged to receive the optically modulated light and to deflect a second linearly polarized light having a second linear polarization axis corresponding to the Y-axis, a projection lens arranged to project the second linearly polarized light onto a screen; and a trim retarder disposed between the liquid crystal display panel and the polarization beam splitter, the trim retarder having an in-plane retardance greater than a residual in-plane retardance of the liquid crystal display panel and having a slow axis, wherein the azimuthal angle of the slow axis of the trim retarder is less than 45 degrees from the first linear polarization axis; characterized in that the trim retarder has an asymmetric profile of net linear retardance versus angle of incidence, when measured along the slow axis plane of the trim retarder; wherein the trim retarder is orientated such that an azimuthal angle of the slow axis of the trim retarder is in a quadrant that mirrors a quadrant containing the slow axis of the liquid crystal display panel about the second linear polarization axis, to provide a system contrast level that is substantially unaffected by at least one of different orientations of the slow axis of the liquid crystal display panel and different orientations of the polarization beam splitter, wherein each of said different orientations of the slow axis of the liquid crystal display panel substantially bisects the first and second linear polarization axes in a different quadrant of the liquid crystal display panel and wherein each of said different orientations of the polarization beam splitter is +45 degrees or -45 degrees with respect to the Z-axis; a light source; a polarization beam splitter arranged to receive light from the light source and to transmit a first linearly polarized light having a first linearly polarized light (241, 242) having a linear polarization axis corresponding to the X-axis of a right handed XYZ coordinate system with orthogonal axes; a reflective liquid crystal display panel arranged to optically modulate the first linearly polarized light, the liquid crystal display panel having a slow-axis and a fast-axis; the polarization beam splitter being arranged to receive the optically modulated light and to deflect a second linearly polarized light having a second linear polarization axis corresponding to the Y-axis, a projection lens arranged to project the second linearly polarized light onto a screen; and a trim retarder disposed between the liquid crystal display panel and the polarization beam splitter, the trim retarder having an in-plane retardance greater than a residual in-plane retardance of the liquid crystal display panel and having a slow axis, wherein the azimuthal angle of the slow axis of the trim retarder is less than 45 degrees from the first linear polarization axis; characterized in that the trim retarder has an asymmetric profile of net linear retardance versus angle of incidence, when measured along the slow axis plane of the trim retarder; wherein the trim retarder is orientated such that an azimuthal angle of the slow axis of the trim retarder is in a quadrant that mirrors a quadrant containing the slow axis of the liquid crystal display panel about the second linear polarization axis, to provide a system contrast level that is substantially unaffected by at least one of different orientations of the slow axis of the liquid crystal display panel and different orientations of the polarization beam splitter, wherein each of said different orientations of the slow axis of the liquid crystal display panel substantially bisects the first and second linear polarization axes in a different quadrant of the liquid crystal display panel and wherein each of said different orientations of the polarization beam splitter is +45 degrees or -45 degrees with respect to the Z-axis;