Poul Henningsen started designing the three-shade system in 1925. The first lights using the system were designed for an exhibition in Paris. Throughout his life, PH sought to create glare-free lighting. He wanted to be able to direct light where it was most needed, and create soft shadows while using incandescent bulbs as a light source.
The PH 3- 2½ Wall Sconce is a member of the three-shade family and is one of 19 versions available today. Approximately one thousand different models have been produced over the years and consisted of table, floor and wall lamps, as well as a number of different chandeliers, which were very popular in the 30s for lighting private homes with high ceilings. There were countless combination options. The lights were available in different colors, as well as a range of sizes. The first shades were made of metal with a painted undersurface, such as white, gold or silver depending on whether diffuse, warm or cold light was desired. Glass was later introduced for the three-shade system. In addition to the downward-directed light, glass lamps illuminated the room.
Henningsen was the first person to pursue a scientific approach to light and use the logarithmic spiral as a basis. By using a design based on the logarithmic spiral he achieved even distribution of light over the entire curve of the shade. This even light distribution, together with the diffuse reflection through the glass, made it possible to control glare and shadow. Each shade reduces the amount of light equally, due to their distance from the light source.
The PH light model numbers refer to the shade size. Each top shade had a corresponding set of middle and lower shades. In the pure models, such as the 2/2, the top shade has a size of about 20 cm, with corresponding lower shades. PH 3 – 2½ Wall consists of an approximately 30 cm top shade, but uses lower shades from the 2½ model. These hybrid models were introduced due to the desire to hang pendants at lower heights. The system was also used for wall, floor and table lamps. PH 3- 2½ Wall Sconce was introduced in 2005.