Light & Engineering Vol. 23, No. 2, pp. 70-77, 2015 Svetotekhnika No. 2, 2015, pp. 39-44 INFLUENCE OF AMBIENT TEMPERATURE ON COLOUR PROPERTIES OF LOW-PRESSURE FLUORESCENT LAMPS Przemysław Tabaka Lodz University of Technology, Poland E-mail: przemyslaw.tabaka@wp.pl ABSTRACT The article presents results of laboratory measurements of colorimetric parameters of various fl uorescent lamps of different powers in ambient temperature ranging from +250 C to –250 C in steps of 50 C. Based on registered spectral distribution of radiation, correlated colour temperature and colour rendering index have been determined. <...> In terms of 18 W fl uorescent lamps, different lamp colour’s codes (640, 827, 840) were considered. <...> Additionally, one straight frost-proof fl uorescent lamp of 840 colour’s code and one 18 W compact fl uorescent lamp integrated with a conventional magnetic choke have been measured. <...> Keywords: fl uorescent lamp, ambient temperature, correlated colour temperature, general colour rendering index, colour’s code 1. <...> INTRODUCTION Fluorescent lamps are among the most popular low-pressure lamps. <...> Fluorescent lamps are characterised by a special feature, which has been pointed out in the literature [4, 5, 6, 7]; their luminous fl ux is depen dent on the ambient temperature. <...> However, the literature lacks analysis of colour temperature in terms of changing ambient temperature of those light sources. <...> This paper deals with the infl uence of ambient temperature on colour properties of low-pressure fl uorescent lamps. 2. <...> METHODS FOR DETERMINING COLOUR PROPERTIES OF FLUORESCENT LAMPS Manufacturers of f luorescent lamps usually provide their colour properties by means of a three-digit code, which is preceded by a symbol of the lamp and information about the power of the light source (Fig. 1 a). <...> The fi rst number of the colour code (item 2 Figs. 1a and 1c) provides information about the general colour rendering index (Ra), the two following items (item 1 Figs. 1a and 1c) give information about the colour temperature. <...> Examples of different methods for determining colour properties of straight <...>