Best of 2015: LED and Plasma Lighting for Video

Video needs lighting. This is a statement worth repeating: video needs lighting. Yes, you can shoot available light, and now there are cameras with obscenely high ISO ratings, but think about it¡ªif you are shooting at 100,000 ISO, 400,000 ISO, or 4 million ISO, what is the quality of your light? And what exactly are you shooting? If you are shooting at high ISO ratings, most likely you are shooting in extremely low light, and although you may be able to get a decent exposure, it is unlikely there will be much contrast in your shot. This is a pity, because unless your project calls for dull, lifeless, flat, and even images, then contrast, along with bright and dark references in your shot, are some of the components that have always made moving images come to life for me. It isn¡¯t that you can¡¯t get stunning, emotionally moving images without using lights; it is just that lighting your image allows you so many more creative options than shooting without. With this in mind, I thought I would discuss some relatively new innovations in LED and Plasma lighting.
CRI or TLCI, Which One to Trust?
I want to address one of the more confusing aspects of LED lighting, which has been the CRI (Color Rendering Index) rating. CRI has been the de facto standard as a color rating system for film and video, but it has proven limitations. For one, LEDs can be designed to match the CRI test strips, and this can render a high CRI rating, even though the bulb has poor reproduction of the full color spectrum, providing misleading results. In response to this issue, the Television Lighting Consistency Index rating (TLCI ) was developed. TLCI takes into account how the light will function in a video camera-and-monitor system, as opposed to only measuring the light¡¯s performance on a chip chart. The TLCI provides a much more useful rating of a light source for video production compared to CRI, and I expect to see the TLCI rating supplant CRI as a meaningful rating in the near future.

CRI chip chart
TLCI chip chart

An increased number of color targets is part of the reason that TLCI is supplanting CRI as the color rating standard for video lighting.?
Plasma Lighting
Last April, I was exposed to two new (at least to me) kinds of lighting¡ªPlasma and Remote Phosphor. Now, truth be told, filmmakers have been using a type of plasma lighting since the 1950s¡ªmore commonly known as fluorescent lighting. Fluorescent lighting creates high-energy plasma inside a glass tube; this plasma excites the phosphors on the inside of the bulb, the phosphors glow, and the bulb emits that glow. Soft, virtually directionless, not very powerful, but efficient and cool, fluorescent lights remain a popular choice. However, the plasma light to which l¡¯m referring is nothing at all like the fluorescent lights to which you are accustomed.
Hive Lighting has taken plasma lighting from a large bulb that makes a soft source, to a small bulb the size of a kernel of corn that produces a strong, hard light. Hive Lighting produces two basic fixtures: the Bee and the Wasp, with a CRI greater than 94. They both feature a retro design that has more to do with keeping costs down than design aesthetic. Hive has focused its effort on the design of the bulb, which is a marvel of technological wizardry. The light emitter (bulb) is about the size of a single kernel of corn, although it sits in a housing that is about 5 inches in diameter and three inches thick. The magic of the bulb is that it is filled with various metal salts in an argon gas, and uses RF to excite the salts, which gives the bulb a spectrum similar to that of the sun. The bulb features a variable color temperature range of 4600 to 7000K, and a constant, non-dimmable, output.

Hive Bee lighting system
Hive Wasp lighting system

The Bee is most similar to an open-face fixture and features a 100-degree beam spread for a flood-light effect, while the Wasp is a PAR-style light with a ten-degree spread and accepts a variety of lenses to spread the beam. One of the distinct advantages of this type of plasma lighting is the ¡°bang for the buck¡± it provides when dealing with power. The fixtures draw about 2.3 amps¡ªthe Wasp compares well to a 575W HMI PAR, but only draws about half as much power, while the Bee provides about as much light as a 1.5k open-face tungsten light would, if there were such a bulb, and it draws less than 300 watts, making the Bee/Wasp about five times more efficient than a tungsten bulb. Quite literally, you could put seven of these fixtures on a single 20-amp outlet. If you are looking for a theatrical spotlight, Hive makes the HoneyBee, which features a Source 4 projection lens and is available with either a CMY color gradient wheel or a CTB/CTO wheel.

As promising as the plasma technology is right now, there are some downsides worth noting. First, even though it is extremely efficient, you are not going to power plasma lights from a little camcorder-type battery. The HIVE fixture runs on 90 to 300 Volts AC or, with select HIVE power supplies, 18 to 38 Volts DC, and requires a header cable from the power supply. The color-temperature range is limited to about halfway between tungsten and daylight-balanced light at the low end, which means you will need gels to match it to tungsten. The bulb itself is not dimmable, which means either using scrims or ND gels to lower the light¡¯s output. There is also a mechanical dimming unit specifically made for the Bee and Wasp. This dimming unit resembles the iris of a lens and fits into the light. The downside to this dimming unit is that just by attaching it, your maximum brightness is only 80% of the unit without the dimming unit, and it only dims to 10%. Additional accessories include softboxes and a Source 4 Projection lens. However, in spite of these minor drawbacks, the advantages of plasma lighting¡ªefficient power consumption to light output, low heat, flicker free at any frame rate up to 22 million fps, variable color temperature, and a bulb rated for 30,000 hours of use make this an exciting new lighting technology.

Remote Phosphor LED
Remote Phosphor LED light fixtures are becoming increasingly available, with units being made by BBS, ARRI, and Desisti. In general, remote phosphor LED fixtures use a deep blue-emitting LED to excite a phosphor-coated panel a few inches away from the LEDs¡ªhence the term ¡°remote¡± phosphor. The BBS Area 48 lighting system uses 48 Deep Blue Cree LEDs with a life expectancy of 50,000 hours. The Blue LEDs strike the remote phosphor panel, which in turn glows, emitting visible light. As the remote phosphor panel is filled with the light from the LEDs, it produces a light that does not suffer from the shadow pattern normally associated with LED-array lights. The fixture is a soft light that is comparable to a 1200-watt soft light that draws only 160 watts.

There is, of course, a downside to this unit, as changing the color temperature requires swapping out the phosphor panel, so there¡¯s no spinning a little knob to change color temperature. However, the other advantages of LED lighting remain¡ªlow power consumption, long life, low heat, plus the added benefit of not having a multi-specular pattern on your subject. Replaceable remote phosphor panels provide a CRI rating of between 93 and 95, producing tungsten (3200K), daylight (5600K), 2700K, 4300K, 6500K, Chroma Blue, and Chroma Green.

The ARRI SkyPanel Remote Phosphor system operates similarly, and features replaceable panels optimized to produce light with color temperatures of 2700K, 3200K, 4300K, 5600K, 6500K, 10000K, and Chroma Green, with CRI between 94 and 98. SkyPanel is available in two sizes: the S30-RP and the S60-RP. Both units feature DMX dimming from 100 to 0%, a 110-degree beam spread and 50,000-hour bulb life. At 25.4 x 11.8″ the S60-RP is nearly twice as wide as the S30-RP, which measures in at 14 x 11.8″. For more on the ARRI SkyPanels, check out this link to an informative article on the ARRI SkyPanels-RP, as well as an embedded video of the lights in action, at NAB, in 2015.

Desisti has introduced two different-sized remote phosphor units, the Soft LED 2 and the Soft LED 4, with remote phosphor panels to match daylight and tungsten. The Desisti panels produce a light with a CRI rating between 91 and 95, while the fixtures feature daisy-chainable main power and DMX, which makes these units well suited for hanging in a grid. Accessories include intensifiers and honeycomb grids for light control.

I hope you¡¯ve enjoyed this glimpse into some of the interesting developments in LED and Plasma lighting, and remember¡ªyou need lighting.