In this paper we present a High Dynamic Range viewer based on the 120-degree field-of-view LEEP (Large Expanse Extra Perspective) stereo optics used in the original NASA virtual reality systems. By combining these optics with an intense backlighting system (20 Kcd/m2) and layered transparencies, we are able to reproduce the absolute luminance levels and full dynamic range of almost any visual environment. This is important because it allows us to display environments with luminance levels that would not be displayable on a standard monitor. This technology may enable researchers to conduct controlled experiments in visual contrast, chromatic adaptation, and disability and discomfort glare without the usual limitations of dynamic range and field of view imposed by conventional CRT display systems. In this paper, we describe the basic system and techniques used to produce the transparency layers from a high dynamic range rendering or scene capture. We further present a series of psychophysical experiments demonstrating the device's ability to reproduce visual percepts, and compare this result to the real scene and a visibility matching tone reproduction operator presented on a conventional CRT display.