Introduction to Film Lighting Fixtures

Color Temperature and CRI

• Color temperature refers to the "color" of white light emitted by a light source, measured in degrees Kelvin.
• The highest possible CRI (Color Rendering Index) is 100, attributed to a perfect black body (e.g., tungsten light source, sun).
• CRI measures a light source's ability to properly reveal the color of an object compared to an ideal or natural light source.

Light Sources

• Tungsten (Quartz Halogen/Tungsten Halogen):
  • Operate at a higher temperature than normal incandescent tungsten bulbs.
  • Produce a warm light, but can be corrected with blue color gels to simulate daylight.
  • Continuous spectrum of light from near ultraviolet to infrared.
  • Near perfect color rendition.
  • Advantages: low cost, does not use mercury, better color temperature than standard tungsten, longer life, instant on, and dimmable.
  • Disadvantages: extremely hot, high power requirement, sensitive to oils, and can explode.
• HMI (Hydrargyrum Medium-Arc Iodide):
  • Metal-halide gas discharge medium arc-length lamp.
  • Contains mercury vapor mixed with metal halides.
  • Capable of high light output and luminous efficiency (up to 115lm/W).
  • Emits a 6000K color temperature light, closely matching natural sunlight.
  • Advantages: high light output, high efficiency, flicker-free light, and can be dimmed.
  • Disadvantages: relatively high cost, high power requirement, requires an external ballast, and can explode if dropped.
• Fluorescent:
  • Uses the excitement of low-pressure mercury vapor to produce UV light.
  • Phosphor coating on the inside of the glass tube glows, giving off light in the visible spectrum.
  • Capable of generating up to 100 lumens per watt.
  • Spectrum of light emitted depends on the mix of phosphors used.
  • CRI up to 99 can be achieved.
  • Color temperature can vary from 2700K to 6500K.
  • Advantages: high efficiency, low power requirement, low cost, long lamp life, cool, and capable of soft even lighting.
  • Disadvantages: flicker can be a problem, and domestic fluorescent installations may have a low CRI.
• LED (Light Emitting Diode):
  • Solid-state semiconductor device.
  • Extremely efficient, but limited in overall light output.
  • Monochromatic, producing only a single wavelength of light.
  • Can be daylight or tungsten balanced, sometimes switchable or having variable color temperature.
  • CRI rating can be over 90.
  • Advantages: soft, even lighting, pure light, high efficiency, low power consumption, excellent dimming, long lifespan, environmentally friendly, and insensitive to shock.
  • Disadvantages: high cost.

Light Fixtures

• Open Faced:
  • Used to create hard light that casts hard shadows.
  • Not much more than a housing and reflector for the bulb.
  • Examples: 800W "Redhead" and 2000W "Blonde".
• Fresnel:
  • Uses a special type of lens divided into concentric circles.
  • Evens out the light and allows for the beam to be varied from flood to spot.
  • Examples: Arri Junior 650W Fresnel Tungsten.
• Practicals:
  • Considered any light source that will appear in the scene.
  • Examples: table lamps, interior light sources, and hand-held flashlights.
  • Often existing bulbs are swapped out for those of different wattage or color temperature depending on the needed effect.