The direct estimation of the luminosity of coloured light sources

Padgham, C A

doi:10.1016/0042-6989(71)90078-2

Cited by 10 publications

(3 citation statements)

References 16 publications

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“…Newhall (1940) states quite clearly that for untrained Os the tendency is "to see chromatic colors as lighter than does the more experienced observer." For aperture colors, Boynton and Kaiser (1968) and Padgham (1971) obtained a similar relationship. The present experiment differs from all these in that it provides the 0 with a scale upon which to make his lightness judgment, but why this procedure should make him give more darker judgments is not clear.…”

Section: Discussionsupporting

confidence: 58%

The psychological relationship between lightness and saturation

Davidoff

1974

Perception & Psychophysics

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Lightness and saturation, though independent in a physical sense, have often been seen to be psychologically related. The first experiment uses a multidimensional scaling technique to again verify this nonindependence for untrained as. A further experiment, using a matching technique, quantifies this relationship, giving the extent of the error in lightness for varying levels of saturation. This relationship is found to be independent of hue if saturation is measured by the colorimetric purity of the hue. Errors in value (lightness on the Munsell system) were found to be linearly related to colorimetric purity.

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Section: Discussionsupporting

confidence: 58%

The psychological relationship between lightness and saturation

Davidoff

1974

Perception & Psychophysics

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“…If one calculated lumen level is higher, it is reasonable to assume that the perceived brightness will be higher, even though we cannot say by how much. However, there are notable exceptions to this such as the HelmholtzKohlrausch effect (Kohlrausch, 1923;Padgham and Saunders, 1966;Padgham, 1971), where highly saturated lights are Luminous flux and lighting levels for domesticated mammals and birds frequently judged to be 'brighter' than whites and near-whites of the same calculated luminance. The constant of proportionality, k m , in Equation (1) is in effect determined by the internationally agreed definition of the lumen: the luminous output of monochromatic light at a wavelength close to 555 nm is defined to be 683 lumens/W.…”

Section: Calculation Methodsmentioning

confidence: 99%

Calculating luminous flux and lighting levels for domesticated mammals and birds

Saunders

Jarvis

Wathes

2008

Animal

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This paper considers whether photometric calculations using standard human spectral sensitivity data are satisfactory for applications with other species or whether it would be worthwhile to use bespoke spectral sensitivity functions for each species or group of species. Applications include the lighting of interior areas and the design of photometers. Published spectral sensitivity data for a number of domesticated animals (human, turkey, duck, chicken, cat, rat and mouse) were used to calculate lighting levels for each species and compared with those derived from standard CIE human photopic and scotopic functions. Calculations were made for spectral power distributions of daylight, incandescent light and 12 fluorescent sources commonly used to light interiors. The calculated lighting levels showed clear differences between species and the standard human. Assuming that the resulting effects on retinal illuminance determine the overall perception of the level of light, there may be applications where these differences are important. However, evidence is also presented that the magnitude of these inter-species effects are similar to, or smaller than, those arising from other optical, physiological and psychological factors, which are also likely to influence the resulting perception. It is also important to recognise that lighting-related parameters such as the good colour rendering of surfaces, the avoidance of glare from lamps and other factors that may be species related are sometimes of greater importance than the lighting levels. Our results suggest that a judicial choice of three spectral sensitivity functions would satisfy most circumstances. Firstly, where the overall sensitivity is maximal in the medium to long wavelengths, the standard CIE photopic function will suffice, chicken, turkey and duck fall in this category. Secondly, in a small number of cases where the sensitivity centres on the short to medium wavelengths, the CIE scotopic function should be used, e.g. for the scotopic cat, photopic rat and photopic mouse. Finally, where an animal is also sensitive to the UV region of the spectrum and there is a significant component of UV radiation, then an additional measure of the UV response should be included, as for the photopic rat and photopic mouse.

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“…It follows that in normal situations, that is outside the walls of a visual laboratory, the calculations based on formula (1) work reasonably well only in the case of low saturation signals . But there exists a need for the assessment of the luminance-brightness relationships of more saturated signals, widely used in everyday life [19,38] .…”

Section: Introductionmentioning

confidence: 99%