After dark, advertising lights and neon lights in shopping malls and hotels are dazzling, and even some intense light hits the sky, making the night feel like a day, creating an "artificial day". This phenomenon makes it difficult for people to fall asleep at night, leading to inefficiencies during the day.

People who have been in this environment for a long time also experience symptoms of neurasthenia, such as dizziness and insomnia. The normal biological clock is disrupted, and the central nervous system of the human brain is severely affected. There are growing complaints and public complaints about light pollution caused by outdoor wall washers and signs.
Different positions of wall washers must be combined with different lighting designs.

Lights should be in harmony with the area to be decorated, the history and culture, the surrounding environment and architectural style, and use different shapes, colors and brightness to express and ambience. The design of outdoor lighting must have integrity and aesthetic effect. At the same time, lighting design is also an art.