Norman Lamps, Inc.

Photo projection lamps are specialized high-intensity bulbs designed for slide projectors, overhead projectors, enlargers, and photographic equipment requiring intense, color-correct illumination. These lamps must produce substantial light output in a compact form factor, maintain accurate color temperature for proper photographic rendering, and achieve this performance while surviving the extreme operating temperatures that projection applications create. The lamp literally determines whether a projector can produce bright, clear images or delivers dim, poorly rendered results.

Slide projectors and overhead projectors use these lamps to create the intense illumination needed to project readable images in ambient room lighting. The bulb sits in a precisely positioned reflector system that focuses light through the slide or transparency and projection lens. The lamp must produce enough lumens to create visible projection even in partially lit rooms – typically 1,000-3,500 lumens or more depending on projection distance and screen size. The compact filament acts as a nearly point-source allowing the optical system to focus light efficiently through the projection path.

Photographic enlargers use projection lamps to expose photographic paper during the printing process. The lamp illuminates the negative, and the enlarger lens projects the image onto photographic paper below. Color accuracy is critical in enlargement work – the lamp's spectral output affects how colors render in the final print. Enlarger lamps typically operate at lower intensities than projection lamps but must maintain consistent color temperature and even illumination across the negative area. Many enlarger lamps use tungsten-halogen technology for consistent color and long life.

Common lamp types include tungsten-halogen lamps in various wattages (150W-500W typical) and configurations, specialized projection lamps with specific reflector designs, and some metal halide lamps in professional projection equipment. The designation codes often indicate wattage and sometimes base type – for example, an ELH lamp is a 300W projection lamp, while a DNE lamp is 150W. These codes matter because projectors require specific lamps matched to their optical systems – using the wrong lamp affects brightness, focus, and in some cases can damage the projector.

Base types vary by lamp power and projector design. Many projection lamps use specialized 2-pin or bayonet bases designed for secure mounting and easy alignment in the projector's reflector housing. Some use medium screw bases (E26) or mogul bases (E39). The base must align the filament correctly in the optical path – even a millimeter of misalignment can significantly degrade projection quality or focus. Some projection systems use lamps with integral reflectors (where the reflector is part of the lamp), simplifying alignment.

Operating life for projection lamps is typically quite short – often 25-75 hours – due to the intense operating conditions required to produce the necessary light output. Running the filament hot enough to generate sufficient lumens dramatically reduces lifespan compared to general illumination lamps. This short life means projection equipment users need to maintain spare lamps and track operating hours to perform timely replacements before lamps fail during important presentations or printing sessions. Some projectors include hour meters to help track lamp life.

The transition away from film-based projection toward digital projection has reduced demand for traditional photo projection lamps, but they remain necessary for maintaining legacy equipment. Many educational institutions, houses of worship, businesses, and individuals still operate slide projectors and overhead projectors requiring these specialized lamps. Photographic darkrooms using traditional enlargement processes continue needing enlarger lamps, though digital photography has reduced traditional darkroom work substantially.

Common Lamp Types: ELH (300W), DNE/DNF (150W), EKE/EKP (150W-250W), various enlarger lamps (75W-250W typical), specialized projection lamps matching equipment requirements

Base Types: 2-pin (GY5.3, GX5.3, others), bayonet, medium screw (E26), mogul (E39), various specialty bases. Alignment critical for optical performance.

Typical Wattages: 75W-500W depending on application. Higher wattages for projection (150W-500W), lower for enlargement (75W-250W)

Applications: Slide projectors, overhead projectors, photographic enlargers, specialized projection equipment, some scientific and industrial applications