Why did the study use indirect luminaires with visible lenses rather than totally indirect fixtures?
The researchers felt it was important to compare the best indirect lighting then available with the best parabolic lighting then commonly available in order to provide as fair a comparison as possible. In the open office areas, the low-brightness visible lenses are claimed by the manufacturer to provide a higher satisfaction level because they provide a higher level of perceived illumination, a contention supported by earlier studies (Bernecker, Penn State University, 1984 and 1986). In the enclosed offices, the lensed indirect fixture provides a superior luminous environment to other commercially available indirect luminaires because the lens provides an extremely widespread distribution designed especially for enclosed areas.
