Ding's first big project was in 2002, when she was sent by a Beijing company to rejuvenate the Shangri-La Hotel on the city's West Third Ring Road.

She used halogen lamps in the lobby because they're closer to the daylight spectrum and closer to interior decoration's original intent. She used fluorescent lamps at dinner tables and washroom sinks.

"A hotel's lighting design is very complicated. It's more like an orchestra, where there are cellos, violins and harps. Here, they are large-area lights, small-area lights, functional lights, artistic lights and so on," Ding explains.

Adjustment is also very important. The hotel's customers - mostly businessmen - don't expect a sharp contrast when they move from outside into the lobby or the meeting room. So Ding designs lights to be brighter in the daytime but dimmer at night, when customers are expecting a relaxed and cozy environment.

"So, it requires an artistic mind and logical thinking," Ding says.

But lighting design is unpredictable. Interior designers and architects use rendered pictures to illustrate their designs but a light designer relies on experience and imagination.

Beijing's Raffles City Shopping Mall was especially difficult because it has two overlapping facades, the exterior of which is glass.