A Rational Methodology for Estimating the Luminous Flux Based upon Color Primaries from Digital Projection Displays —Edward F. Kelley, Karl Lang , Louis D. Silverstein and Michael H. Brill ABSTRACT: A standard methodology exists for estimating the flux from front projection displays by sampling the projected illuminance of a white source signal. With the advent and use of white projection primaries, a dramatic increase in flux can be achieved over the combination of red, green, and blue primaries alone. However, when a white primary is used saturated-color areas in an image are constrained to low flux levels relative to the display maximum and further undergo a perceptual compression in relative lightness. As a result, bright saturated colors cannot be rendered accurately and the appearance of full-color imagery is distorted. The display of color-accurate imagery does not generally use the white primary due to these problems, and thus there is a need for providing an equivalent flux measurement that will better describe the performance of all projectors when rendering full-color imagery. Background research and a method utilizing the source-signal color primaries are described.