An electric lamp assembly 10 for emitting near infrared radiation includes a reflector housing 20 and a lamp vessel 24 positioned within the reflector housing. A source of illumination 28 is enclosed within the lamp vessel. A continuous multi-layer interference film 40 on an exterior surface 42 of the lamp vessel transmits near infrared radiation within the range of 850-1100 nm and is substantially non-transmissive towards visible radiation.