A high-end shopping center in Seoul, South Korea, attracts customers with a flashy lighting scheme on the outside featuring LEDs and a user-friendly control system.

» This structure is not just another pretty face in fashionable dress-like the customers inside. The lighting mechanics behind the kaleidoscopic façade for the Galleria West Shopping Center in Seoul, South Korea, are one of a kind. Designed by UN Studio Architects, with Rogier van der Heide of Arup Lighting, the building's exterior is slowing traffic and passersby at this busy intersection, and attracting visitors to the high-end shops it houses.

Client Hanwha Stores wanted 'the most modern, trendy, and fashionable store in Korea to beat the competition,' says the project architect, Astrid Piber of UN Studio. 'They wanted something that was constantly changing, from day to night, and from the viewer's perspective on the street.'Displaying everything from text to amorphous images recalling the sea or sky, the façade has arguably achieved this goal. With a 'refresh rate' of 20 updates per second (faster than the average consumer-grade video camera, notes Van der Heide) over each of the 13,000 DMX channels and with 16 million potential colors, the system is capable of an infinite variety of scenes. 'It's very smooth,' says Van der Heide. 'DMX can go higher. There are systems that have 32 updates per second, but they never have this many channels.' This rate provided both the stability and fluidity the designers were seeking for a surface of this size.

The shell, which from afar looks like colored bubble wrap, is actually formed of 4,330 overlapping glass discs, 33 inches in diameter and a half-inch thick. 'Since it is a fashion mall, we wanted to create a 'dress' for the building, with a texture like fabric,' says Van der Heide, who experimented with various materials, including metal mesh. The laminated glass discs, however, exhibited the most exciting qualities in the studio. Full-scale mock-ups with nine discs enabled the team to test glass and light combinations and angles, as well as different glass finishes. Given the building's location on a major shopping thoroughfare, the designers worried that glare from the discs might blind drivers. They chose a custom-made solution of acid-etched glass on both sides, with a dichroic coating in between: The outside treatment minimizes glare from the sun, while the inside creates a more uniform light distribution. The dichroic interlayer, meanwhile, interacts with the angle of the sun and the viewer to add a level of intricacy and color during the day, when the artificial lighting is not utilized. The laminated treatment ensures that during occasional typhoons, the layers that form the 40-pound discs will not separate and fall, only crack.

The LED light sources that give life to the building's exterior were also custom designed by the team in conjunction with Dutch company Xilver, which has since the completion of the project made the product part of its standard offering. 'They had something like this in the pipeline,' says Van der Heide, who had worked with Xilver on other projects. 'We gave a big push because we needed it. It was a collaboration.'

Together, the manufacturer and designer tackled a major challenge for the industry when it comes to LEDs: color mixing. One LED fixture comprised of four 1W LEDs (one red, one blue, and two green) backlights each disc. After multiple tests, it was determined an extra green component would help balance the color. 'Every reputable manufacturer today has a color-changing LED fixture, but almost all of them have a pinkish/magenta hue. I was looking for something very crisp and cool,' says Van der Heide. The mockups demonstrated that an extra green LED (proposed by Xilver) would create a neutral hue.

Perhaps in deference to the pop culture that has welcomed colorfully animated buildings, the shopping center's façade works like a large low-res television, with each LED fixture acting as one pixel. It is the control system that converts and transmits data to the 40,000-square-foot screen that most sets this project apart. 'This is the first time the user doesn't need lighting programming skills,' explains Van der Heide, who wanted an intuitive solution. 'You can create animations using any software that you are comfortable with, and just upload it to a server.' Once the data on the server is converted into a proprietary protocol based on TCP/IP, it then travels over 32 DMX lines (or universes), which control 512 channels each, to deliver the many commands that 'dress' the façade. The system can also be connected to and programmed wirelessly from a laptop on the street, for example.

Several days of training had Hanwha Stores ready to create its own façade displays, which included images of snow falling and a 'Merry Christmas' message during the recent holiday. While not exactly what Van der Heide had in mind when he developed the façade design, he admits 'that is part of the game. You make it interactive and easy to program, and the risk is they are going to do awful things with it. But they may also do wonderful things.' emilie w. sommerhoff

project Galleria West, Seoul, South Korea
client Hanwha Stores, Seoul, South Korea
architect UN Studio Architects, Amsterdam
lighting designer Arup Lighting, Amsterdam
photographer Christian Richters
manufacturers CGE Glass (laminated glass discs), e:cue (control system), Xilver (LED fixtures)