LEDs transform department store in Seoul

Galleria - nighttime LED lighting manufacturer Xilver delivered 5000 color changing LED lights to completely encapsulate the façade of a luxurious department store in Seoul, Korea.

The Galleria department store is completely covered by a series of 80 cm-diameter frosted glass discs which are backlit by LED lights. The RainDrop lights contain 3 LEDs and are supplied by Xilver, an LED lighting manufacturer based in the Netherlands.

The LEDs change the color of each of the discs and thus enable the creation of a vivid play of colors and graphics to be displayed on the exterior of the store, which was once had a monotone concrete façade.

Galleria - daytime The department store, which houses the world’s top fashion brands such as Louis Vuitton, Prada and Bulgari, was looking to make an instant statement. The concept for the façade was created by Rogier van der Heide and Simone Collon of Arup Lighting, and architects Ben van Berkel and Caroline Bos of the firm UNstudio.

Galleria - before LEDs The building undergoes a complete transformation during the day and evening. The glass is covered by a special dichroic foil supplied by 3M, and the color of the façade changes from green to amber, depending on the position of the sun and the viewing position. In the evening, the Xilver LED lights light the frosted glass discs. "The subtle daytime looks of the building changes to something completely expressive and outgoing during the night," says lighting designer Rogier van der Heide.

Lighting system

After being contacted by van der Heide in March 2004, Xilver developed a custom, waterproof, color-changing LED fixture that would be strong enough to color a frosted glass disc of 80 centimeter in diameter. It was also necessary to have control over the color of each of the 5000 lights.

Xilver developed a controller that can control up to 4 individual RGB LED lights called RainDrops. These RainDrops are individually addressable and thus controllable through any DMX-512 device.

Rogier van der Heide A particularly big challenge was to ensure that each of the individual lights produces matching colors, despite the inevitable variations from LED to LED. "When I choose 'blue at 80%', I want the same blue everywhere on the building," said van der Heide. "With such a large number of LEDs (5000 per color), there can be a wide variety of hues."

To overcome this problem, Xilver developed a unique LED color-calibrating system. "We choose a red, green and blue LED as the benchmark for all other LEDs," says Tommy Voeten, general director of Xilver. "By varying the intensity and wavelength of the three colors one can adjust the colors of one fixture to match the benchmark fixture. Furthermore, we developed special software to automatically adjust the intensity and wavelength of each fixture related to the LEDs used from a particular binning."

Demo system Xilver developed the lights to be controlled by the DMX-512 protocol, and E:Cue developed the hardware and software to provide the DMX signals to the lights. "The challenge of the project was the very large number of DMX lines," says Philipp van Beeck of E:Cue. "Before this project, our hardware could handle 16 DMX lines, while in this case we had to control 32 lines." In total something like 15,000 DMX channels are controlled by E:Cue's Programmer software and 8 E-Link Ethernet nodes.

Each lighting fixture of Xilver acts as a pixel of a video screen. The E:Cue programmer software intelligently combines lighting control with the display of videos and bitmaps through the Xilver color changing LED lighting fixtures. All kind of effects can be added easily to these images.

"All in all this was an exciting project," says Tommy Voeten, "I think that the lighting designers and the architects set a new landmark in urban architectural design."