Poul Henningsen developed the PH 5 in 1958 in response to constant changes to the shape and size of incandescent bulbs by bulb manufacturers. At the introduction of the PH 5, Poul Henningsen wrote the following: After 33 years of basically Christian behaviour I have converted to Islam in my relationship to the manufacture of incandescent bulbs. For a generation I have believed that consideration for the consumer and common sense would prevail, but now I have become a fatalist. I have accepted fate, and with Louis Poulsens permission I have designed a PH fixture which can be used with any kind of light source, Christmas lights and 100 W metal-filament bulbs. Although a fluorescent tube would be too much to ask in the existing form!. The PH 5 was introduced as a classic new product, and no one knew at the time that it would eventually become synonymous with the PH light. Irrespective of how the light is installed or the light source used, the PH 5 is and remains completely glare-free. The fixture was christened PH 5 due to the 50 cm diameter of the main shade. Poul Henningsen wanted to improve the colour reproduction characteristics of the light source in the PH 5. Small red and blue shades were therefore inserted to supplement the colour in the part of the spectrum where the eye is least sensitive the red and blue areas thereby subduing the light in the middle yellow-green region where the eye is most sensitive. The light fixture's design has been regularly updated as light sources have developed. The PH 5 is available in the classic white version, a modern white model and in six colour versions, where the colour is darkest at the top and gradually lightens moving down from shade to shade. The struts are purple on the classic model and bronze-coloured on the other seven versions. The reflector ring colour contrasts with the other hues. To celebrate the 60th anniversary in 2018 of this beloved pendant, Louis Poulsen released the PH 5 in an edition that pairs copper shades and white tiers and in 2019 with brass shades. The new metallic-and-white combination highlights Henningsens shade system design and adds new dynamism to one of his most recognised forms, with the mirror-like metal tiers reflecting their surroundings. The metal shades a untreated and will patinate over time. All of these editions are also available in the scaled down PH 5 Mini (30cm diameter), which was added to the PH 5 family in 2017.