Abstract: A transparent, fixed reference pattern is mounted on one side of a rigid, transparent sheet placed in front of a television monitor screen to enable an operator to more easily align an internally generated monitor display pattern with the fixed pattern during a calibration procedure. The side of the transparent sheet adjacent the monitor screen is covered with a semi-reflective material to reflect the reference pattern back through the sheet to the viewer so that the viewer, by causing the reflected pattern to align with the actual reference pattern, can ensure that his viewing position is exactly perpendicular to the sheet and the surface of the screen, thereby eliminating parallax problems. The monitor is then calibrated to make the generated pattern conform to the reference pattern.