Lumen

What does an Irish photographer do with a burned out light bulb? Saves it for use in his dark room.

Lumen Outputs of Different Lamp Types

Lumen Type	Typical Lumen Output
GLS 100 Watt	1300
12V 50 Watt dichroic TH	950
1500 Watt QI	33000
Fluorescent: 18 Watt	1150
Fluorescent: 30 Watt	2400
36 Watt	3300
36 Watt Triphos	3300
58 Watt	4600
Mercury Vapour: 250 Watt	13700
Mercury Vapour: 400 Watt	24000
Metal Halide: 250 Watt	20500
Metal Halide: 400 Watt	38000
High Pressure Sodium: 250 Watt	27500
High Pressure Sodium: 400 Watt	47500

Low Temperature Operation
Standard fluorescent fittings can be operated down to -20 degrees C if a 38 mm lamp and special starter are used.

Lumen output will be 20% of normal when lamp is at -10 degree C. The lower lumen output must be considered when calculating the number of fittings required.

Plastic sleeves are available to provide some thermal insulation to a lamp operating in a low temperature environment.

Lowest operational temperature of other types of discharge lamps:

	HPS ok down to - 60 degree C
	MH ok down to - 20 degree C
	MV ok down to - 5 degree C