Scandinavia Design

PH4½-4 Glass pendant

Louis Poulsen – Poul Henningsen, 1931

espace client

15% off with DESIGN15

Louis Poulsen, Danish Design Lighting
Suspension PH4½-4 Verre Louis Poulsen – Poul Henningsen, 1931
Suspension PH4½-4 Verre Louis Poulsen – Poul Henningsen, 1931

The 4½-4 Glass Pendant is based on a main shade of approximately 45 cm, to which are added the two low shades of the 4/4 model. It is one of the "hybrid" models designed to be suspended at low heights. The system was also used for floor, table and wall lamps. 

Suspension PH4½-4 Verre Louis Poulsen – Poul Henningsen, 1931
Suspension PH4½-4 Verre Louis Poulsen – Poul Henningsen, 1931

PH 4 ½-4 Pendant

Dimensions Ø45 x H41 cm

Shades Mouth-blown white opal glass. Anti-glare disc: Purple, spun aluminium

Body High lustre chrome plated, extruded aluminium

Cable length 3 m

Weight 3.2 kg

Light source 1 x E27

Class Ingress protection IP20. Electric shock protection I w. ground

The 4½-4 Glass Pendant is part of the PH family of lamps with 3 shades, born in the winter of 1925-26 for an exhibition in Copenhagen. In 1926, Poul Henningsen said of this new system: "The real innovation of the PH luminaire is that it produces glare-free as well as economical lighting. 

It's quite easy to create glare-free lighting (indirect light or with a thick shade) if some of the light can be wasted. It's also easy to create highly efficient luminaires if you ignore the fact that they are highly irritating to the eyes. But creating lighting that is both economical and glare-free is an art.

Suspension PH4½-4 Verre Louis Poulsen – Poul Henningsen, 1931

As early as 1925, Poul Henningsen came up with the idea of using a logarithmic spiral to control the brightness and nuance of luminous light, with each shade equally reducing the amount of light emitted as a function of distance from the bulb. The transitions in brightness between each shade were harmonic, and the relative size of the shades and their positioning were determined by the need to reduce glare, the arrangement of the light and the need for light distribution, according to some remarkably simple principles. The concept was extremely flexible: not only was it possible to achieve different sizes, but also to shape the light with white, silver or gold surfaces. Poul Henningsen imagined that in a restaurant the light should be warm and intimate, and that a golden surface should be used, unlike in a hospital where white surfaces should be used. 

The first luminaires were all made with metal shades, then Poul Henningsen developed a variant in opal glass with a sandblasted lower section. The shades let 12% of the light through and contributed to the ambient lighting of the room, while most of the light was reflected downwards. For the pendant lamps, the sizes of the 3 shades were in a ratio of approximately 3:2:1. For table lamps, the lower shades had to be smaller. This gave rise to the PH 2/1 and PH 3/2 ratios.

Poul Henningsen

Poul Henningsen

Born in Copenhagen, Poul Henningsen's mother was the famous Danish actress Agnes Henningsen. He never qualified as an architect, but studied at the Technical School in Frederiksberg (Denmark) from 1911 to 1914, and then at the Technical College in Copenhagen (1914-1917).

He started out practising traditional functionalist architecture, but over the years his professional interests evolved to focus mainly on lighting, which is what he is most famous for. He also branched out into writing, becoming a journalist and author. For a brief period at the start of the Second World War, he was chief architect of Tivoli Gardens in Copenhagen. But like many other creative people, he was forced to flee Denmark during the German occupation, and soon became a vital part of the Danish colony of artists living in Sweden.

His long 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-in-chief of the business magazine "NYT". Louis Poulsen's CEO at the time, Sophus Kaastrup-Olsen, offered PH the magazine because he had been sacked from the Danish newspaper he was working for (his views were too radical).

Poul Henningsen's pioneering work on the relationship between light structures, shadows, glare and colour reproduction, compared with man's need for light, remains the foundation of the lighting theories still practised by Louis Poulsen.