A light bulb situated at 15 cm from samples. Light employed was a 6W linear fluorescent (F6T5/D, GE lighting # 10028) together with the following characteristics: Initial Lumen (NOM) 230, Median Lumen (NOM) 185, Colour temperature 6500 K, Nominal initial lumen per Watt (NOM) 38. Other certain parameters for instance spectral, energy distribution or electric characteristic might be checked in the b