Visibility of radiant energy

Gibson, K. S.; Tyndall, E. P. T.

doi:10.6028/nbsscipaper.154

Cited by 125 publications

(60 citation statements)

References 15 publications

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“…The relative brightness to the human eye on the one hand, and to the photographic emulsion on the other hand, of tungsten filament light can be discovered from a knowledge of (a) the luminosity curve of a constant energy spectrum (Gibson & Tyndall, 1923), (b) the distribution of energy with wave-length in the tungsten filament light (Priest, 1922), and (c) the spectral sensitivity curve of the photographic emulsion to tungsten filament light, described in the previous section. The ratio between the area below the luminosity curve for tungsten filament light and that below the photographic spectral sensitivity curve for the same light, gives us the photographic effectivenessof each lux of this light; we will denote this by E w' For daylight, a similar factor can be derived from (a) the luminosity curve as above, (b) the distribution of energy with wave-length in daylight (Davis & Gibson, 1931), and (c) the spectral sensitivity curve of the photographic emulsion to daylight, derived from the similar curve for tungsten filament light by means of the two energy distribution curves; we will denote this factor by Ed'…”

Section: Standardization and Calculation Of The Resultsmentioning

confidence: 99%

“…The approximate sensitivity curves shown in Fig. 2 were obtained by making a series of exposures of different durations and plotting the wave-length at which a standard amount of blackening had been produced, against 1/tP, where p is the Schwarzschild Curve E is derived from the luminosity figures of Gibson & Tyndall (1923) and the distribution of energy with wave-length in tungsten filament light given by Priest (1922).…”

Section: B Gaslight Paper (Illingworth Slogas Matt Soft)mentioning

confidence: 99%

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The photographic method for rècording average illuminations

Bayliss

1938

J. Mar. Biol. Ass.

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(Text-figs. 1-3)The photo-electric cell is admirably suited for measuring instantaneous illuminations, but does not lend itself readily to the measurement of the total illumination received on a surface over a long period of time, or the average illumination received during that time, although it has been used for this purpose (Atkins & Poole, 1936a). The method used by these authors, however, would be difficult to use in the field and away from laboratory facilities. The photographic method, on the other hand, is admittedly not capable of yielding results of high precision, but the simplicity of operation, and absence of elaborate and bulky apparatus, make it suitable for use in the field.In principle, the amount of blackening produced in a photo-sensitive emulsion is used as a measure of the total illumination received; in order to increase the range over which measurements can be made, a neutral tint wedge, of suitable slope, is placed in front of the emulsion, and the distance along the wedge at which a standard amount of blackening is produced is taken as a measure of the illumination. The standard amount of blackening is best defined as that amount which is produced, in the absence of the wedge, by a known illumination acting for a known time. The method has inherent limitations, particularly when used for long-period observations, which result from (a) the failure of the reciprocity law, (b) the uncertainty in the value of the wedge constant, and (c) the varying sensitivity of the emulsion to lights of different wave-lengths.

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Section: Standardization and Calculation Of The Resultsmentioning

confidence: 99%

Section: B Gaslight Paper (Illingworth Slogas Matt Soft)mentioning

confidence: 99%

The photographic method for rècording average illuminations

Bayliss

1938

J. Mar. Biol. Ass.

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“…From the beginning of luminous efficiency research, experimenters have had difficulty with inter-subject variability Gibson and Tyndall 1923). A variety of factors, including differences in optical properties including pupil size, macular pigment density, cone photopigment absorption, neural processing and match criteria are responsible for this inter-subject variability.…”

Section: Discussionmentioning

confidence: 99%

“…It is common in investigations of luminosity to have subjects and data sets that are difficult to work with. In their landmark study Gibson and Tyndall (1923) noted that:…”

Section: Discussionmentioning

confidence: 99%

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Luminous Efficiency Functions at Higher Intensities

Harrington¹

2004

PsycEXTRA Dataset

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Public reporting burden for this coliection of Information is estimated to average 1 hour per response, Including the time for reviewing Instructions, searching existing data sources, gathering and maintaining the data needed, and completing and reviewing the collection of information. heterochromatic brightness matching, were used to measure changes in luminance efficiency functions with increasing levels of light adaptation. Both measurement techniques were performed using the same optical system and the same seven healthy adults as subjects. Measurements were taken at four reference stimulus intensities, 1,10, 100 and 1000 foot-lamberts. Luminous efficiency was found to depend on both the technique and the reference stimulus intensity with which the measurements were taken.For heterochromatic brightness matching, luminous efficiency increased for longer wavelengths as reference intensity increased. Peak luminous efficiency shifted from approximately 540nm to greater than 600nm with increasing intensity for all seven subjects. Peak luminous efficiency was constant for flicker photometry across all intensities but the function narrowed slightly at 100 foot-lamberts. AbstractTwo psychophysical measurement techniques, flicker photometry and successive heterochromatic brightness matching, were used to measure changes in luminance efficiency functions with increasing levels of light adaptation. Both measurement techniques were performed using the same optical system and the same seven healthy adults as subjects. Measurements were taken at four reference stimulus intensities, 1,10, 100 and 1000 foot-lamberts. Luminous efficiency was found to depend on both the technique and the reference stimulus intensity with which the measurements were taken.For heterochromatic brightness matching, luminous efficiency increased for longer wavelengths as reference intensity increased. Peak luminous efficiency shifted from approximately 540nm to greater than 600nm with increasing intensity for all seven subjects. Peak luminous efficiency was constant for flicker photometry across all intensities but the function narrowed slightly at 100 foot-lamberts.

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Determination and Significance of the Photopic Retinal Visibility Curve

Ludvigh¹

1940

Archives of Ophthalmology

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Visibility of radiant energy

Cited by 125 publications

References 15 publications

The photographic method for rècording average illuminations

The photographic method for rècording average illuminations

Luminous Efficiency Functions at Higher Intensities

Determination and Significance of the Photopic Retinal Visibility Curve

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