Photometric and Colorimetric Measurements of Luminaires Using Goniometer and spectrophotometer in a Dark Chamber

This article reports the actual performance of a newly-renovated dark chamber in the Engineering Physics Program, Institut Teknologi Bandung, by measuring the photometric and colorimetric characteristics of a high-bay and a street luminaire. Both luminaires had light-emitting diodes (LED) as their light sources. The dark chamber has dimensions of 11.8 m × 5.8 m × 3.5 m; its interior surfaces are painted matte black or covered with black fabric curtains. Using the installed goniometer at a fixed distance of 10 m, the photometric characteristic of the luminaires could be accurately measured at approximately 15 minutes per luminaire. The measurements were conducted for four C-planes and γ-angles ranging from -90° to 90° at 1° resolution. Using a portable spectrophotometer at distances of 10, 8, 7, 6, and 4 m, the colorimetric characteristic of the luminaires, including correlated colour temperature, peak wavelength, colour rendering index, and standard deviation colour matching, could be accurately measured. Variation of distance has a very small influence (coefficient of variance < 2%) on the colorimetric results of the high-bay luminaire; however, it has some influence on those of the street luminaire. Since the tested street luminaire had asymmetrical luminous distribution, it is therefore recommended to conduct the colorimetric measurement at smaller distances of less than 6 m.