Measuring light in field experiments using dummies and objects: A study of concert lighting

Abstract

Lighting experiments were performed in a real context populated with dummies and objects. Using the King's College Chapel in Cambridge as a case study, two field surveys of concert lighting were performed, one with the chapel empty and one with it occupied. In each survey, photometric data were collected under three electric lighting conditions and from six different viewing positions. A comparative analysis indicates that the data gathered from the occupied space represent the luminances more accurately, present a more detailed description of the light distribution, and provide a more extensive set of variables characterising the geometrical details of the visual scene. This study demonstrates the importance of using occupied spaces and considering the presence of occupants in field studies, which could be useful for obtaining a more complete understanding of complex luminous environments.

Methods for assessing the effects of spatial luminance patterns on perceived qualities of concert lighting

“…A detailed description of the experimental space and layout has been given in Lo and Steemers. 54

Figure 1Four electric light settings: (a) Setting I, Interim Lighting: Peripheral lights - 4 sets of light fixtures were mounted on the North and South walls. Each set consisted of a Megaman 320 w energy-saving fluorescent lamp (Table 3(c)) and 2 supplementary 16 w Philips MasterLed spotlights (Table 3(d)); (b) Setting II, Interim Plus: Peripheral lights and an overhead spotlight - Setting I + A Megaman 320 w energy-saving fluorescent lamp (Table 3(c)) suspended at 4 m high; (c) Setting III, All Lighting: Peripheral lights, overhead rig lights and an overhead spotlight - Setting I + Setting IV; (d) Setting IV, Rig Lighting (control setting): Overhead rig lights and an overhead spotlight - 28 Havells Sylvania Hi-Spot 95 halogen lights (Table 3(e)) and a Megaman 320 w energy-saving fluorescent lamp (Table 3c)) suspended at 4 m high (see Table 3 for detailed specifications)

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“…63 Measuring procedures have been presented previously. 54 We processed and analysed the images and photometric data in relation to the observer's visual field, aiming to provide a comprehensive mathematical and spatial analysis of light for the chapel. For this to be achieved, we adopted image zoning and abstraction techniques (Figures 6 and 7): Using binary masks, the images were partitioned based on the structure of the visual field.…”

“…The experiments were conducted in a performance area of 139 m 2 under four electric light settings (Figure 1). Similar to our previous field investigations on occupied spaces, peripheral wall lighting (crown uplight 54 Seventy-eight participants were recruited from across the University of Cambridge to take part in these evening experiments. Prior to the experiment, the participants were briefed about its aim and the procedure.…”

“…An appraisal of concert lighting for the King's College Chapel in Cambridge was prompted by complaints about its low illuminance, uneven luminous distribution and the visual distraction said to be caused by the present rig lighting installation. Having recognised the importance of performing lighting experiments in real, complex and occupied settings, 54 we took the opportunity to use the chapel as a test bed for our methodological developments: (i) examine the applicability of methods in a real setting with architectural significance; (ii) investigate techniques to extract meaningful patterns and data from HDR images, and (iii) identify possible subjective-objective connections.…”

A Comparison of Two Different Light Booths for Measuring Color Difference of Metameric Pairs

“…A studied revealed that the luminance level in several light booths varied from 100 to >1000 cd/m 2 [11]. There are studies that show how correlated color temperature and illuminance affect color perception [12][13][14][15] and users' feeling [16][17][18][19].…”