6000W HMI

Overview

A "6000W HMI" (also known as a 6K HMI) refers to a 6-kilowatt class spotlight that uses an HMI discharge lamp. HMI stands for Hydrargyrum Medium-arc Iodide – a metal halide gas discharge lamp that produces daylight-like light in the range of approximately 5600 to 6000 Kelvin. This allows artificial light sources to be mixed with sunlight and skylight without requiring color correction of the light color.

The 6kW power level is an established standard within the HMI series, which typically ranges from small heads to very large units (common levels: 575 W, 1.2 K, 2.5 K, 4 K, 6 K, 12 K, 18 K). The 6K head is thus in the upper mid-range: significantly more powerful than a 4K, but without the power consumption and weight of the very large 12K and 18K units.

Construction Types

The 6000W HMI head is available in two optical designs that serve different purposes on set:

• Fresnel: provides a directed, cleanly cut beam of light with adjustable focal length from spot to flood. For example, the ARRI Compact 6000W Fresnel can be focused from around 15° (spot) to about 50° (flood). Fresnel heads are suitable for controlled key and effect lighting.
• PAR: produces a very intense, largely parallel beam with a long throw. PAR heads are preferred for illuminating backgrounds, for window light through diffusion, or as a hard source into a reflector/bounce surface.

The head is operated via an electronic ballast, which ensures high-frequency, flicker-free operation for high-speed and digital recordings. At ARRI, for example, a 6/12 kW ballast covers this power class.

Lamp

A single-ended HMI lamp is used in the 6K head. The following values refer to a specifically documented lamp, the Osram HMI 6000W (Digital, Order No. 59584):

Note: Depending on the manufacturer and variant, 6K HMI lamps are offered with a nominal color temperature of 5600 K or 6000 K. Like all HMI lamps, they shift slightly in color temperature over their lifespan and should be handled with care as high-pressure discharge lamps according to the manufacturer's specifications (explosion protection, cool-down time).

Set Usage

The 6000W HMI is a workhorse for daylight setups: as a key light for exterior or interior day shots, for "pushing" window light from the outside, for illuminating larger areas, or – in the PAR version – as a powerful bounce source. Due to its high power, it requires a suitable power supply and the correct ballast; however, compared to 12K and 18K units, it remains more portable and can be operated with smaller generators, making it a flexible size for many productions.