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Bará, S. (2017). Variations on a classical theme: On the formal relationship between magnitudes per square arcsecond and luminance. Intl J of Sustainable Lighting, 19(2), 77.
Abstract: The formal link between magnitudes per square arcsecond and luminance is discussed in this paper. Directly related to the human visual system, luminance is defined in terms of the spectral radiance of the source, weighted by the CIE V(l) luminous efficiency function, and scaled by the 683 lm/W luminous efficacy constant. In consequence, any exact and spectrum-independent relationship between luminance and magnitudes per square arcsecond requires that the last ones be measured precisely in the CIE V(l) band. The luminance value corresponding to mVC=0 (zero-point of the CIE V(l) magnitude scale) depends on the reference source chosen for the definition of the magnitude system. Using absolute AB magnitudes, the zero point luminance of the CIE V(l) photometric band is 10.96 x 104 cd·m-2.
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Bará, S. (2019). Black-body luminance and magnitudes per square arcsecond in the Johnson-Cousins BVR photometric bands. Photon. Lett. Pl., 11(3), 63.
Abstract: A relevant amount of light pollution studies deal with the unwanted visual effects of artificial light at night, including the anthropogenic luminance of the sky that hinders the observation of the celestial bodies which are a main target of ground-based astrophysical research, and a key asset of the intangible heritage of humankind. Most quantitative measurements and numerical models, however, evaluate the anthropogenic sky radiance in any of the standard Johnson-Cousins UBVRI photometric bands, generally in the V one. Since the Johnson-Cousins V band is not identical with the visual CIE V-lambda used to assess luminance, the conversion between these two photometric systems turns out to be spectrum-dependent. Given its interest for practical applications, in this Letter we provide the framework to perform this conversion and the transformation constants for black-body spectra of different absolute temperatures.
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Cho, H. M., Lee, M. K., Chang, S. J., & Kim, S. (2015). Analysis on Luminance of Outdoor Signboards of Commercial Areas in Seoul at Night Considering Light Pollution. J. Korean Soc. Living Environ. Sys, 22(4), 583–595-589.
Abstract: As the city is commercialized, the number of stores is increased and it also makes outdoor billboards’ number increased accordingly. And signboards on the street make pedestrians unpleasant, making light pollution by light reflection. In this study, we measured the luminance to target the outdoor signboards of commercial area in Seoul. On the basis of the obtained results, the External system showed high luminance values, and the luminance values of Letter-type system were lower. Furthermore, the measured value at the midnight time was higher, and we considered that the more floating population bring about the high luminance value of the External system. The signboards of External system should be avoided, the Letter-type system should be recommended.
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Fiorentin, P., & Boscaro, F. (2019). A method for measuring the light output of video advertising reproduced by LED billboards. Measurement, 138, 25–33.
Abstract: Improving knowledge of the light output of digital billboards is important to better assess their effect on driver distraction when they are installed along roads. In this work the emission of an LED based billboard is measured when playing advertising video-clips. In particular the average and the maximum values of the luminance are evaluated. The same video-clips are also analyzed when shown on an LCD monitor, aiming at separating the variability of the videos and of the playing device. The results allow to evaluate an utilization factor of the billboard: the videos have an average luminance around 11% and a peak luminance of 35% of the maximum luminance obtainable from the billboard. The power consumption of the billboard is measured, aside the photometric analysis. The luminance of the device are found linearly dependent on both the power and the effective current absorbed by the device from the grid, with a discrepancy within 6%. It could be a useful information for billboard manufacturers to qualify their product when they do not own photometric instruments.
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Ho, C. Y., Lin, H. T., & Huang, K. Y. (2011). A Study on Energy Saving and Light Pollution of LED Advertising Signs. Amm, 121-126, 2979–2984.
Abstract: Lighting advertising signs not only play an important role in outdoor lighting environment in Taiwan, but also become the main factor of energy consumption in urban areas at night. Light-emitting diode (LED) has been gradually used in advertising signs due to its advantages. However, in order to be conspicuous and legible in the daytime, signs that are excessively bright may result in considerable light pollution and energy waste at nighttime. Therefore, this research aims to measure the luminance of LED signs and traditional internally lighted signs, and analyze the light trespass from each signage. Based on the research results, the energy consumption from a LED full color screen is 12 times more than a traditional internally lighted sign per day. Statistically, all kinds of LED signs are much higher than traditional internally lighted signs in the percentage of excessive brightness and average luminance value. As for the light trespass, since the vertical illuminance on facade facing the signs increases with the increase of the sign area or the decrease of the distance between the sign and the facade, the vertical illuminance on facade facing the signs would exceed the limit of CIE even if the luminance of the signs achieves the standard of CIE in terms of the general conditions in Taiwan. This happens to LED full color screens in particular and thus results in considerable obtrusive light. To sum up, in order to reduce unnecessary energy consumption and improve the nighttime lighting quality for outdoor environment, this research recommends the luminance limitation for light dimming of LED advertising signs should refer to the zoning, time period, and sign area.
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