Spectral Characteristics of Slide Projection Systems

Abstract

Spectral characteristics of various slide projection systems are investigated by means of newly developed spectral radiometer, which scans the visual spectral range from 400 nm to 700 nm.
It is found that (1) spectral distributions of the light emitted from the projection system are influenced by the transmissions of condencer lenses, projection lens, and heat absorbing filter and spectral reflectances of various day-light screens, and (2) particularly light-outputs decrease at the blue and red ends of the visual spectral range owing to the heat absorbing filter and projection lens, and (3) spectral reflectance of various kinds of day light screens, lenticular, beaded, and matt type, are generally flat over the whole visual range, except the blue end of the spectrum.
Moreover, colors of the color films, projected on the screen are somewhat different from those of Original color charts, but seems to become similar to original colors, as the colos temperature of the light sousces increase.