White powder coated aluminum, white lacquered on the inside.
In 1925 the renown Danish master of light Poul Henningsen developed his 3-shade system, a structure which makes the lightsource glare-free, using the right shadow angles. This idea has laid the foundations of his famous PH lamps which ensure soft, glare-free light. The lamps are named according to their shade size. Each top shade has a corresponding set of middle and lower shades.
Louis Poulsen launched the PH 4/3 pendant in 1966. It is a simplification of a lamp Henningsen designed in 1929 for which he earned the highest distinction at the world exhibition in Barcelona. Its design follows the general 3-shade system based on the logarithmic spiral, with the centre of the light source positioned at the centre of the spiral. The insides of the shades are painted white to provide a uniform, comfortable light distribution.
Watch PH: Philosphy of light, a documentary about Poul Henningsen here:
read more about Poul Henningsen
Poul Henningsen (1894-1967) was the very first Danish lighting expert. He pioneered in examining the relationship between light structures, shades, glare and color in view of the human need for light.
From 1911-1914 he studied architecture at the Technical school of Frederiksberg and then at the Technical College in Copenhagen until 1917, but never completed his training as an architect. After quitting College he worked in journalism for 8 years, first as an art critic for the magazine Klingen and later for the newspapers Politiken and Extra Bladet. In 1920 Henningsen established himself as an independent architect. He started out as a traditional functional architect, but over the years his professional interests developed mainly towards illumination.
From 1924 onwards Louis Poulsen began producing his designs. and over the next 40 years, Henningsen's lights became so intertwined with Danish culture that they acquired their own collective noun: PH-lamps. In 1925 the first PH-lamp won an award at the World Fair in Paris. This lamp was the result of 10 years of research and ingeniously designed to avoid glare and provide a soft, warm glow. Henningsen made the light shine through several layers without the bulb being visible to its user. He also experimented with different colors on the inside and outside.