Dimmable architectural lighting that meets the demands of HDTV

An Austrian multifunctional arts venue says it has achieved a breakthrough in lighting technology. Architectural luminaires designed to complement the flow of natural light and accentuate the building’s shapely forms have been customised to serve an extra purpose – to provide ideal lighting conditions for high-definition TV broadcasts.

Dimming LEDs has always been a tricky business. Users want the smooth, seamless effect we are conditioned to expect from incandescent sources. LED drivers have not always been up to the job, producing incremental changes in light output or intensity that are interpreted by the human eye as flicker – particularly at low levels. High-definition television cameras are even more sensitive to flicker.

Of course, there are plenty of LED drivers capable of providing smooth dimming to very low levels, but development has focused on specialist lighting in environments such as television studios or conference rooms for audiovisual presentations. What has been achieved at Montforthaus is architectural lighting capable of dimming down to zero, seamlessly and without flicker, in cool colour temperatures between 2700 and 5000K.

With the special solution for Montforthaus, we have developed a luminaire that is truly unique”

Philippe Rettenbacher, Zumtobel

Montforthaus, in the Austrian town of Feldkirch near the Liechtenstein border, is a new culture and congress centre that has replaced an older building. Officially opened in January 2015 after five years of planning and construction, it now hosts a diverse range of events including concerts, fairs, conferences and symposiums.

An LED lighting solution was sought for the usual reasons: energy efficiency, cost savings, reduced maintenance burden, and environmental friendliness. The luminaires chosen had to complement the architecture and provide the necessary light levels and ambience. But because many events were expected to be televised, the lighting in certain key spaces had to meet the needs of HDTV broadcasting.

The building, designed by the Berlin office of Hascher Jehle Architektur, stands in the shadow of the historic Schattenburg castle. Its organic shape and flowing lines, combined with transparent façades and the glass dome of the foyer, are designed to minimise the barrier between exterior and interior, allowing daylight to flow through the building.

Flexible for functions
The lighting concept had to support and complement this principle of permeability, accentuating the contoured lines of the architecture while ensuring a uniform natural lighting effect. Crucially, the system had to be flexible enough to adapt to different functions, creating the right mood for stylish receptions, grandiose concerts and academic symposiums. Diverging ceiling heights of between 2.4 and 10m also had to be taken into account.

The installation was devised by architectural and stage lighting design consultancy Belzner Holmes/Light Design Engineering (LDE) in conjunction with Zumtobel. LDE was chosen for its technological expertise and proven ability to work with Zumtobel to solve technical issues – in this case how to achieve the necessary dimming performance. After extensive testing and investigation, the decision was made to customise an existing luminaire.

The starting point was Zumtobel’s Panos Infinity family of modular LED downlights. Panos Infinity combines a sophisticated design by Sottsass Associati with advanced functionality. Most importantly, the luminaires’ colour temperature can be tuned from warm white to neutral to cool according to need. The selected colour temperature range of 2700-5000K is best suited to broadcasting because it comes closest to matching daylight.

The customised MFH-Panos luminaire uses specially developed Zumtobel technology to achieve a smooth, flicker-free transition through DMX control in the all-important 10 to 0 per cent range, where flicker is most likely to be picked up by cameras. A series of experimental HD recordings made in the studios of Austrian television broadcaster ORF using the lights confirmed the absence of flickering or visual disturbance.

Use of DMX and Dali controls ensures the ratio of warm and cold white light throughout the building can be controlled individually. Depending on the necessary response rate, the integrated 28, 30 or 40W downlights are equipped with intelligent Dali or DMX technology that enables separate control of each luminaire.

Individual control of the lighting scenarios in areas such as the Great Hall helps create the right mood for every event, from cool white to neutral and warm. A combination of MFH-Panos and Zumtobel’s Ondaria circular luminaires with concave opal diffusers sets the scene in the Montforthaus café.

Eighteen Zumtobel products are used in Montforthaus, including Lightfields Evolution in the stairwell and Craft for general lighting for the stage area. Altogether more than 2,500 luminaires were installed, including about 750 of the different MFH-Panos variants.

The customised downlights were created specifically for Montforthaus, but given the growing appetite for high-definition televised events, it is a timely innovation. ‘With the special solution for Montforthaus, we have developed a luminaire that is truly unique,’ says Philippe Rettenbacher, Zumtobel project manager. ‘The MFH-Panos has been designed specifically to meet the needs of our customer, but the potential for global success is already clear.’

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