Investigations of the subjective balance between illuminance and lamp colour properties

Atli

et al. 2013

Light sources are available in a variety of spectral power distributions (SPDs) and this affects spatial brightness in a manner not predicted by quantities such as illuminance. Tuning light source SPD to better match the sensitivity of visual perception may allow the same spatial brightness but at lower illuminance with potential reductions in energy consumption. Consideration of experimental design was used to review 70 studies of spatial brightness. Of these, the 19 studies considered to provide credible evidence of SPD effects were used to explore metrics for predicting the effect of SPD but did not provide conclusive evidence of a suitable metric, in part because of incomplete reporting of SPD characteristics. For future work, these data provide an independent database for validating proposed metrics.

Section: Methodsmentioning

confidence: 99%

Section: Characteristics Of the Visual Scenementioning

confidence: 99%

Lamp spectrum and spatial brightness at photopic levels: A basis for developing a metric

Atli

et al. 2013

“…In addition to the differences between these models [16][17][18][19][20][21][22][23][26][27][28] , it is important to appreciate that none of them predict any effect of SPD in photopic conditions, yet it is well established that SPD does influence brightness perception in photopic conditions [30][31][32][33][34] . Indeed, there are empirical models for predicting brightness under different light sources in photopic conditions based on this effect 32,[34][35][36][37] .…”

Section: Models Of Mesopic Visionmentioning

confidence: 99%

Light source spectrum, brightness perception and visual performance in pedestrian environments: a review

Boyce³

2005

This review considers the impact of light source spectral power distribution (SPD) on brightness perception and visual performance in mesopic conditions, with emphasis on the comparison of metal halide (MH) and high pressure sodium (HPS) lamps. Models of mesopic vision predict that SPD is a significant variable in that at a HPS photopic luminance of 0.100 cd/m 2 , MH need only produce about 0.070 -0.075 cd/m 2 to be seen as equally bright. However, attempts to validate the predictions of these models in the field have met with mixed success. As for visual performance, experimentation has shown that there are effects of SPD in mesopic conditions, but the magnitude of these effects depends on the nature the task. Three alternative approaches are suggested for comparing light sources with different SPDs in mesopic conditions.

“…This null condition data shows that at the lower illuminance (300 lux) the mean illuminance of the adjusted lighting was higher than the reference, although not significantly so, 13 whereas at the higher reference illuminances (500 lux and 700 lux) the mean illuminances of the adjusted lighting were significantly lower than the reference (p<0.01). 13 The effect may also be present in other brightness matching studies 4,8 but the published results do not enable it to be identified.…”

Section: Response Contraction Biasmentioning

confidence: 87%

“…[4][5][6] Two stimuli are presented in juxtaposed spaces, these spaces ranging from small bipartite fields, 7 to side-by-side booths, 4 to adjacent symmetrical rooms. 8 The test participant observes both stimuli simultaneously, typically using binocular vision and natural pupils.…”

Section: Brightness Matchingmentioning

confidence: 99%

Evidencefor response contraction bias in side-by-side matching tasks

2007

A recent study of lamp spectrum effects at mesopic levels employed side-by-side matching to investigate brightness. The results revealed an unexpected effect, identified here as a response contraction bias, normally only expected when judging individual stimuli. Response contraction bias causes subjective responses to be biased toward the middle of a response range. Although the bias is small its effect on brightness matching can be significant if the test procedure does not employ appropriate counterbalancing.