The PH 3½-2½ Glass Table lamp was designed in 1928 and is one of many advanced projects undertaken by Poul Henningsen in the development of his world-famous three-shade system from 1926.
The fixture is designed based on the principle of a reflective three-shade system, which directs the majority of the light downwards. The shades are made of mouth-blown opal three-layer glass, which is glossy on top and sandblasted matt on the underside, giving a soft and diffuse light distribution.
Poul Henningsen was born in Copenhagen by the famous Danish actress Agnes Henningsen. He never graduated as an architect, but studied at The Technical School at Frederiksberg, Denmark from 1911-14, and then at Technical College in Copenhagen from 1914-17.
He started practicing traditional functionalistic architecture, but over the years his professional interests changed to focus mainly on lighting which is what he is most famous for. He also expanded his field of occupation into areas of writing, becoming a journalist and an author. For a short period at the beginning of WWII, he was the head architect of the Tivoli Gardens in Copenhagen. But like many other creative people, he was forced to flee Denmark during the German occupation but soon became a vital part of the Danish colony of artists living in Sweden.
His lifelong collaboration with Louis Poulsen began in 1925 and lasted until his death. To this day, Louis Poulsen still benefits from his genius. Poul Henningsen was also the first editor of the company magazine “NYT”. The CEO of Louis Poulsen at the time, Sophus Kaastrup-Olsen, gave the magazine to PH as a gift because he had been terminated from the Danish newspaper he worked for (his opinions were too radical).
Poul Henningsen's pioneering work concerning the relations between light structures, shadows, glare, and color reproduction—compared to man’s need for light remains the fondation of the lighting theories still practiced by Louis Poulsen.