The safe use of Source Four luminaires to illuminate works of art, objects in a museum or similar delicate photosensitive objects requires knowledge of the ultraviolet radiation emitted. This document provides measured data for Source Four luminaires using a range of light sources and lenses to allow the lighting professional to make an educated judgment as to those emissions when creating a lighting design. It should be stressed however that, although care has been taken to ensure that these figures are as accurate as possible, there is no substitute for measuring the actual emission on site as local conditions may significantly affect the final result. These figures should be used for guidance only.
Representative sample luminaires were tested to the methodology suggested in IESNA RP-30-96 with three lamp versions to provide worst case results (See Note 2). These results were then extrapolated using known data to encompass other Source Four luminaires and other lamp varieties (Tables 1 and 2). To aid the application of the results, conversions and multiplying factors are also provided for different dimming levels of the luminaires (Table 3). Testing was carried out both with and without an Optivex™ UV filter in the luminaire.
IESNA RP-30-96 suggests defining UV for these purposes as all electromagnetic radiation with wavelengths between 300 and 400 nm and the luminaire?s total emission as the total radiation with wavelengths between 300 and 700 nm. This methodology was used for these tests and the results are presented in three different formats (Columns A, B and C) in tables 1 and 2:
Column A UV percent (%): This expresses the total UV energy between 300 and 400 nm as a proportion of the total energy between 300 and 700 nm.
Column B Microwatts of UV per lumen (µW/lm): This expresses the UV energy emission relative to the luminous output.
Column C Microwatts per square centimeter at 50 lux (µW/cm2):Unlike the first two figures this is an absolute measure and is referred to the lighting level of 50 lux often recommended for photosensitive display materials.
1.Note: This data is applicable as worst case data for the Source Four, Source Four jr, Source Four Zoom and Source Four jr Zoom Ellipsoidal luminaires when fitted with the standard, EDLT or zoom lenses.
2.Note: This data is applicable as worst case data for the Source Four PAR EA, Source Four PAR MCM and, Source Four PARNel luminaires when fitted with any of the standard lenses.
Dimming an incandescent lamp reduces the UV output in two ways; firstly the overall output of the lamp reduces and, secondly, the percentage of UV emitted further reduces as the lamp runs cooler. For a range of dimming from 100% down to 50% the UV output is approximately as indicated in table 3.
Notes to the data:
Optivex™ is a trademark of Applied Coatings Group.
Electronic Theatre Controls, Inc.
Ultraviolet (UV) Content of ETC Source Four Luminaries