The Purkinje Effect in Luminance Measurements of Air Force Phosphorus
Abstract
A formula is derived for relating effective and photopic units of luminance by means of Weaver's interpolated data (J. Opt. Soc. Amer. 39:281, 1949) for the mesopic luminosity functions. The formula is applied to the spectra of 4 typical AF luminescent phosphors; results are compared with experimental data. Individual values of B'/B reveal considerable dispersion around the mean value, particularly as the match becomes more heterochromatic; B' is the specified luminance measured in effective units of luminance, and B is the luminance of the same area in photopic lamberts. Averaged values agree with the B'/B curves. Weaver's data is tentatively accepted for conversion between effective and photopic units in luminance measurements of luminescent materials. A study of the effect of color on the results of the Purkinje effect showed that colors furthest removed from that of the standard 2360 deg K source exhibited the most pronounced change in B'/B with decreasing luminance. The blue phosphor produced over 4 times as much visual response per unit energy at the lowest luminances than at luminances above 1 ft-lambert; the red phosphor produced about 1/5 the amount.
Document Details
- Document Type
- Technical Report
- Publication Date
- Oct 01, 1952
- Accession Number
- AD0005353
Entities
People
- Daniel I. Pomerantz
- John R. Cannon