05.25.2010 11:55 AM
Originally featured on BroadcastEngineering.com
Sky News overcomes lighting challenge at Gherkin studio
Sky News has chosen Gekko Technology LED lighting for its newsroom on the 15th floor of the Gherkin in London's financial district.
The studio, which is used for the daily business update “Jeff Randall Live,” has as its backdrop a view directly through an exterior glass wall. Airing at 7:30 p.m. each weekday, the cameras have to contend with the setting sun because the background of the studio is due west. Care was taken to achieve camera positions that used nearby buildings to mask direct views of the sun. However at sunset, doing so can be hard to achieve consistently.
The initial solution considered involved using HMI fixtures running through DMX-controlled dimmer shutters into soft boxes. This introduced complications, including control, power draw and the large amount of heat that multiple HMIs produce, especially when used in a confined space. Sky then approached Gekko Technology via Broadcast and Production Services to investigate an LED-based solution. Sky is no stranger to LED lighting but was concerned about avoiding color shift when dimming and relatively low intensity.
Gekko specified a solution based on a range of its fixtures powered by kleer color, the company's color-tunable LED light engine. The solution centers on kezia hard-source lights.
Fully color tunable, the kezia fixtures provide a high volume of even light with color temperature that is accurate at points between 2900K and 6500K. Color temperature stability is maintained via a feedback loop built into each light. If a shift in output is detected as a consequence of rising ambient temperature, for example, the kleer color system automatically adjusts to the temperature specified. Calibration of units as they leave the factory also ensures consistency from lamp to lamp.
For backlighting, the kezia 50 was deployed, which requires only 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. This made rigging a relatively straightforward process with no undue loading on the ceiling-hung grid.
As well as the high light output requirement, the lux levels were specified to be as low as 100lux in winter, requiring 100:1 dimming with no shift in color. Gekko’s solution was able to meet this challenge without requiring dimmer shutters, consumable neutral-density gels or scrims.