Photoflood 500W

Overview

A Photoflood 500W is not a fixture, but a light bulb: an overloaded tungsten incandescent lamp operated for photo and film lighting, referred to in German as Fotolampe (common brand name: Nitraphot). It is deliberately operated at a higher voltage than a normal filament of this wattage would withstand. This causes the filament to glow hotter, producing two effects: significantly higher light output (up to double that of a normal household incandescent bulb of the same wattage) and a precisely defined, high color temperature. The price for this is a drastically reduced lifespan.

500 watts is one of the most common power ratings in this lamp family, which ranges from approximately 250 to 1000 watts. The lamp is screwed into simple reflector sockets or floodlight housings (often with an E26/E27 screw base) and delivers soft, widely dispersed floodlight.

Principle of Operation: "Over-run"

The characteristic feature is operation "at an actually too high operating voltage" (English: over-run). The hotter filament shifts the color temperature into the range defined for artificial light and increases brightness. However, since the filament operates closer to its melting point, the tungsten evaporates faster. The lamp loses light output and color quality (blackening of the bulb, drop in color temperature) especially towards the end of its lifespan and is therefore often replaced before it burns out completely.

Technical Data

500-watt photoflood lamps are offered in two color temperature standards. The following ANSI types are the common 500W representatives (values for the North American 120V versions):

• 3200 K (Type B): tuned to classic tungsten/artificial light; mixable with Fresnel lenses, spot lamps, and other tungsten equipment.
• 3400 K (Type A/S): higher color temperature, shorter lifespan (according to technical literature, in the order of about 10 hours).
• Luminous Flux: a 500W ECT delivers initially in the order of around 13,000 to 14,000 lumens.
• Europe: versions with E27 screw base for 230 V (e.g., Nitraphot).

Use on Set

For decades, photoflood lamps were the affordable standard for studio and amateur film lighting before halogen, HMI, and LED sources largely displaced them. Today, they have become rare on professional sets but still appear in simple floodlight reflectors, in archive/vintage setups, and in photo reproduction. Two points are primarily relevant in practice: Firstly, only one color temperature should be mixed on set (do not combine 3200 K and 3400 K separately), otherwise the camera will not achieve a clean white balance. Secondly, the short lifespan must be planned for – have enough spare lamps on hand and replace lamps with visibly blackened bulbs, as they will otherwise become too hot and too dark. Like all incandescent lamps, photoflood lamps dissipate most of their energy as heat and become very hot during operation.