Lighting perfection

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(Photo courtesy Litepanels)

SCREEN AFRICA EXCLUSIVE:

Not many production tools have had a more profound impact on the television broadcast industry than set lighting. Not only does lighting enable the audience to see clearly what the director wants them to see, it creates mood, focuses attention and – more technically – affects and controls the colour temperature, quality and intensity of the broadcast image, making lighting a powerful element of any television production.

Studio, stage and production lighting has recently undergone the most significant transformation in the technology in over a century thanks to the development of the blue LED.

Relatively low cost, low-power portable light-emitting diode (LED) lighting solutions have been on the market for more than 10 years now, but have been more of a compromise than an improvement on existing lighting. LEDs have traditionally been limited by power requirements, size and inaccurate or poor spectral performance.

Just four years ago, Japanese scientists Isamu Akasaki, Hiroshi Amano and Shuji Nakamura were jointly awarded the Nobel prize in physics for their 1990s research and subsequent invention of the blue light-emitting diode, a technology that has touched society in innumerable ways and which has enabled technologies in the broadcast industry that we didn’t think were possible.

As you all know by now, LEDs are devices that emit light when subjected to an electric current. Green and red versions have been around since the 1950s, but creating blue-emitters was a technical challenge that stumped industry efforts for decades. It wasn’t until the 1990s that engineers Isamu Akasaki and Hiroshi Amano, both at Japan’s Nagoya University, in tandem with electrical engineer Shuji Nakamura, then working at Japanese chemicals firm Nichia, succeeded in creating a blue LED.

LEDs are sandwiches of semi­conductor materials. The layers are ‘doped’ with other elements, which provides some layers with extra electrons and others with a surplus of ‘holes,’ where missing electrons leave behind a positive charge. When an electrical current is applied, the electrons and holes combine at the junctions between the layers and emit light as a result.

From the 1980s, physicists focused their efforts on the material gallium nitride as a target for making high-power blue LEDs, but they were faced with several technological hurdles. One was creating thin, high-quality crystals of the material, which are notoriously difficult to grow. Another was ‘doping’ gallium nitride in such a way that it emitted light efficiently. However, Akasaki, Amano and Nakamura persisted with gallium nitride long after their competitors had moved on to other materials, and so the blue LED was born and led to a revolution in the lighting industry.

Blue LEDs, in combination with red and green LEDs, make it possible to produce white light. In more recent times, the development of RGBW (a four-in-one LED chip made up of red, green, blue and white chips) and RGBWW (a five-in-one solution with an extra white chip) has allowed us to make truly accurate, and fully colour-tunable LED lights offering significant power output in the form of large and small studio lights.

Although RGB and RGBW can produce a colour close to white, a dedicated white LED in a RGBWW array provides a much purer white tone and allows you the option of an extra warm or cool white chip. The additional white chip also provides extra scope for colour mixing with the RGB chips to create the huge range of unique shades necessary for film and television productions.

Using software to map and control individual red, green, blue and white LED chips, it has become possible to implement truly accurate correlated colour temperature (CCT) curves over a wide colour temperature range by adding or subtracting (+/-) green in an LED lighting fixture. CCT is a specification of the colour appearance of the light emitted by a lamp, relating its colour to the colour of light from a reference source when heated to a particular temperature, measured in degrees Kelvin (K). It is also possible to precisely factory-calibrate every light individually to match a target profile, which means that every light performs identically. It has also become possible to dial in any colour within the gamut of the light, and so imitate entire gel libraries. Special effects and any number of control protocols can be enabled entirely in software. This kind of precision and control is the future of lighting whether in studio or on location, and has never been possible before.

German motion picture and lighting giants Arri were early adopters and perfectors of LED lighting technology when they formed a subsidiary post-production and creative services company, Arri Media, back in 2015. Their LED lighting technology dominates the market these days, especially their SkyPanel range, which includes the S360 – the largest and most powerful LED soft light available. The SkyPanel is a compact, ultra-bright and high-quality LED soft light that has set new standards for the industry. With a design focused on form, colour, beam field and output, it represents the culmination of more than a decade of research into and development of LED technology at ARRI.

Not to be outdone, US-based Litepanels, a company foundered by a group of Hollywood-based lighting designers, released their flagship RGBWW lighting rig, the Gemini, late last year. The company claims that the Gemini has been designed to give users a daylight-to-tungsten light foundation that then enables them to finely adjust colour shades throughout the full, 360-degree colour wheel. The philosophy behind doing it this way is that users should be able to match a broad range of ambient lighting conditions with more ease. Another plus to the Gemini is the multiple control offerings, through standard DMX, Wireless DMX or Bluetooth control, via an app on your iOS device. These lights have been designed to be stackable and also daisy-chained together, allowing a single designated “master” light to control the others.

There are numerous other players entering the RGBWW field, such as Kino and Cineo Lighting – who produce the Kino Flo Celeb 250, Kino Flo Select 20 and Cineo HSX range, among other offerings – but these battle to compete with Arri and Litepanels on the technical front. If you don’t need all the features like Effects Mode, Colour Mode or even CCT adjustment, then there are plenty of other more value-friendly alternatives available. If you are simply just after a two-by-one soft light that is highly portable and provides pretty accurate colour rendition, then something like the Aladdin BI-FLEX 2 or Westcott Flex Bi-Color LED Mat make a lot more sense.

RGBWW technology has led to a revolution in the lighting industry, so we – and the environment – must thank the research efforts of the three Japanese scientists who successfully developed blue LEDs. It is predicted that by the end of this year, nearly 20% of all power generated worldwide will be saved by people adopting LED lighting solutions in their homes, streets and offices…and, of course, their studios and film sets. Arigatou gozaimasu, guys!

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