Gekko lights up Sky with LEDs21 May 2010
Sky News has chosen Gekko LED lighting for a tricky lighting installation, namely countering the setting sun through the windows at its new London newsroom.
The studio, on the 15th floor of the 180 metre ‘Gherkin’ in London’s financial district, is used for the daily business update Jeff Randall Live, and has a view directly through an exterior glass wall. Airing at 19.30 each weekday evening in HD, the cameras have to contend with the setting sun, as the backdrop is due west. Although care was taken to achieve camera positions that use nearby buildings to mask direct views of the sun, this can be hard to achieve consistently as the sun sets.
The initial solution considered involved using HMI fixtures running through DMX-controlled dimmer shutters into soft boxes. This introduced complications in terms of control, power draw, and the large amounts of heat that multiple HMIs produce in a confined space. Sky then approached Gekko Technology via Broadcast & Production Services to investigate an LED-based solution. Sky has previously used LEDs, but was concerned to avoid colour shift when dimming and relatively low intensity.
The resulting set up uses Gekko’s new kezia hard-source lights, based on its kleer colour tunable LED light engine.
The kezia fixtures provide a high volume of even light, the colour temperature of which is accurate at points between 2900 and 6500 Kelvin. Colour temperature stability is maintained via a feedback loop built into each light. If a shift in output is detected dues to rising ambient temperature, for example, the kleer colour system automatically adjusts to the correct colour temperature. Each lamp is calibrated to ensure consistency.
"As well as the requirement for colour temperature accuracy, the west-facing window demanded very high light levels in the studio," explained Gekko MD, David Amphlett. "The actual requirement was for a maximum of 10,000 lux on the presenter when the sun is on axis with the camera. To achieve this, we recommended a combination of kezia 800, 200 and 50 fixtures installed as key, fill and back lights. The kezia 800 is fitted with four kleer colour light engines, each individually controlled via DMX. These were hung as key lights, oriented directly to cover both the presenter and guests. To avoid hotspots and increase the overall ambient light level, kezia 200 fixtures were hung as fill lights directly above the set, presenter and guests. The kezia 200 uses a 190 Watt LED array and has a similar output (in the white spectrum) to a traditional 1 kilowatt tungsten source."
For back-lighting, the kezia 50 was deployed. This uses 50W of power but equates to a 250W tungsten source. Power supplies for the lights are contained in separately integrated units, each capable of driving up to four lamps, which made rigging simpler, reducing the loading on the ceiling-hung grid.
As well as the high light output requirement, the lux levels were specified to be as low as 100 lux in winter, requiring a 100:1 dimming with no shift in colour. The kezia lights can manage this without requiring dimmer shutters, neutral-density gels or scrims.
"The ability of the kezias to produce such a volume of light makes them a viable alternative to traditional light sources, especially in technically challenging environments such as Sky News’ new City studio in the Gherkin," said George Davies. Sky News Head of Cameras, who oversaw the project. "An ability to change the colour temperature also adds a whole new dimension. which can enhance the images produced, as well as complementing the other technologies we use. Sky News’ new studio provides a stunning backdrop for the Jeff Randall Live programme on Sky News HD and this would not have been possible without this new LED lighting technology."
The projects was delivered by Gekko and BPS in less than six weeks and delivers images comparable with a traditional install, but at reduced power consumption and heat levels and with no change in colour temperature when dimming.