Resolution with ~4000 horizontal pixels. DCI-4K (4096×2160) for cinema, UHD (3840×2160) for broadcast. More image data means more latitude in grading and reframing.
"4K" is the common abbreviation in film lighting for a 4000-watt spotlight. The "K" stands for Kilowatt (1 K = 1000 W) and refers to the device's power consumption – not the image resolution (4K video) and not the color temperature in Kelvin. On set, a "4K" is almost always an HMI spotlight, meaning a daylight-balanced discharge lamp (Hydrargyrum Medium-arc Iodide).
The wattage is part of a whole series of HMI units, which are consistently named on set by their power output. A typical size scale is: 200 W, 575 W, 1.2K, 2.5K, 4K, 6K, 12K, and 18K. The "4K" thus sits in the mid to upper power range and is one of the most frequently used HMI formats for exterior shoots and daylight-dominant sets.
HMI lights are daylight-balanced; their color temperature is around 5600 K, making them suitable for mixing with daylight. Compared to incandescent light (Tungsten, ~3200 K), HMIs are significantly more efficient: watt for watt, an HMI delivers approximately three to four times the light output of a Tungsten spotlight, according to a common rule of thumb. Therefore, a 4K HMI often replaces a considerably more powerful Tungsten fixture on set, with lower power consumption and heat generation.
HMIs require a ballast – magnetic or electronic. Electronic ballasts allow flicker-free operation (important at high frame rates) and usually dimming. The lamp is an AC discharge lamp with a limited lifespan; it ignites with high voltage and requires a short warm-up period.
The 4K is offered in various optical configurations:
| Parameter | Specification |
|---|---|
| Power | 4000 W (= "4K") |
| Light Type | HMI / Daylight |
| Color Temperature | approx. 5600 K |
| Lamp | HMI/MSR discharge lamp, 4000 W (single-ended) |
| Operation | only with ballast (magnetic or electronic) |
Specific dimensions, weight, and light output values vary depending on the manufacturer and type and can be found in the respective data sheet.
As a cinematographer, I particularly appreciate 4K for the enormous flexibility it offers in post-production – I can zoom into the image without any loss of quality or correct framing afterwards. However, the higher resolution demands more precise work when focus-pulling, as even the slightest inaccuracies become much more apparent.
For me as a director, 4K opens up new creative possibilities – I can extract close-ups from a wide shot afterwards without losing quality. This gives me more flexibility with resolution and allows for more spontaneous decisions on set, as not every shot size needs to be filmed separately.
For me as a producer, 4K means significantly higher costs due to expanded storage and processing capacities, longer render times, and more complex data handling. At the same time, it's indispensable for marketing today, as broadcasters and streaming platforms expect and reward 4K content accordingly.
1. Was beschreibt „4K" am besten?
2. Zu welchem Department gehört „4K"?
3. Wie viele verschiedene Fachperspektiven bietet dieser Eintrag?
The Lexikon is part of the Filmfarm ecosystem — alongside budgeting (FilmBalance), an industry magazine (FilmCircus) and crew networking (FilmCall, CrewMesh). One shared vocabulary for the whole production.