TY  - GEN
A1  - Werner, John S.
A1  - Cicerone, Carola M.
A1  - Kliegl, Reinhold
A1  - DellaRosa, Denise
T1  - Spectral efficiency of blackness induction
N2  - The spectral efficiency of blackness induction was measured in three normal trichromatic observers and in one deuteranomalous observer. The psychophysical task was to adjust the radiance of a monochromatic 60–120′ annulus until a 45′ central broadband field just turned black and its contour became indiscriminable from a dark surrounding gap that separated it from the annulus. The reciprocal of the radiance required to induce blackness with annulus wavelengths between 420 and 680 nm was used to define a spectral-efficiency function for the blackness component of the achromatic process. For each observer, the shape of this blackness-sensitivity function agreed with the spectral-efficiency function based on heterochromatic flicker photometry when measured with the same 60–120′ annulus. Both of these functions matched the Commission Internationale de l'Eclairage Vλ function except at short wavelengths. Ancillary measurements showed that the latter difference in sensitivity can be ascribed to nonuniformities of preretinal absorption, since the annular field excluded the central 60′ of the fovea. Thus our evidence indicates that, at least to a good first approximation, induced blackness is inversely related to the spectral-luminosity function. These findings are consistent with a model that separates the achromatic and the chromatic pathways.
T3  - Zweitveröffentlichungen der Universität Potsdam : Humanwissenschaftliche Reihe - paper 040 
Y1  - 1984
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-16897
ER  - 
TY  - GEN
A1  - Werner, John S.
A1  - Donnelly, Seaneen K.
A1  - Kliegl, Reinhold
T1  - Aging and human macular pigment density : appended with translations from the work of Max Schultze and Ewald Hering
N2  - The optical density of human macular pigment was measured for 50 observers ranging in age from 10 to 90 years. The psychophysical method required adjusting the radiance of a 1°, monochromatic light (400–550 nm) to minimize flicker (15 Hz) when presented in counterphase with a 460 nm standard. This test stimulus was presented superimposed on a broad-band, short-wave background. Macular pigment density was determined by comparing sensitivity under these conditions for the fovea, where macular pigment is maximal, and 5° temporally. This difference spectrum, measured for 12 observers, matched Wyszecki and Stiles's standard density spectrum for macular pigment. To study variation in macular pigment density for a larger group of observers, measurements were made at only selected spectral points (460, 500 and 550 nm). The mean optical density at 460 nm for the complete sample of 50 subjects was 0.39. Substantial individual differences in density were found (ca. 0.10–0.80), but this variation was not systematically related to age.
T3  - Zweitveröffentlichungen der Universität Potsdam : Humanwissenschaftliche Reihe - paper 037 
KW  - Macular pigment
KW  - Color vision Aging
Y1  - 1987
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-16836
ER  -