PH lamps

The shift in luminance from shade to shade appears harmonious. The size of the shades and their position is determined by the need to reduce glare, direct light and the requirements for light distribution.

From the start it was clear that the concept was extremely flexible. Fra begyndelsen var det åbenlyst at konceptet var yderst fleksibelt. Not only was it possible to create fixtures in many different sizes, but also with different undersides – either white painted, silver-plated or gold-plated.

These different undersides helped to create different lighting options.

Poul Henningsen imagined that guests at a restaurant wanted lighting that was warm and cosy, and therefore one would choose a gold-plated surface, whereas in a hospital or dentist’s office, one world use the white painted surface.

The first light fixtures were all manufactured with metal shades, but Poul Henningsen also wanted to produce a variant which had a light distribution curve with less downward-facing light. The result was a shade made of opal glass with a sandblasted lower surface.

The glass shades allowed 12% of the light to penetrate and therefore contribute to the general light in the room, while most of the light was still reflected outwards and downwards from the matte undersides of the shades.

The same principles behind the matte metal shades also applied to the new shade material.

This combination worked well when lamps were hung relatively high, but when the pendants were hung at a lower level a more suitable combination was a large overshade with smaller mid- and undershades.

Thus were the PH 2/1 and 3/2 born. The PH 3-shade System started as a solution for pendants, the fixture program was soon expanded to include table, floor and wall versions as well as larger pendants.

As a result of combining different sizes, materials, surfaces, colours and light sources, thousands of variants have been created through the years.

The PH fixtures were designed as a rational lighting system, where the size of the shades, their material and their surface could be combined based on the design of the lamp.

Each size variant of overshade had an accompanying set of mid- and undershades so that the proportion of the shades was roughly 3:2:1.

From the start, one of the base models in the series was the PH 5/5. The first number indicated the diameter of the overshade, and the second number indicated that the accompanying mid- and undershades were created to match that particular type of overshade.

In this case, the 5/5 had an overshade with a diameter of 50cm, a midshade of 31cm and an undershade of 16.5cm.

Before the production of the 3-shade System, Poul Henningsen and Louis Poulsen Lighting worked together on the design of fixtures for the Danish Pavilion at the World Expo in Paris in 1925.

When Henningsen designed these fixtures for the World Expo, he had already played with the idea that the logarithmic spiral might be a suitable basis for the design of a new shade.

The combination of diffuse reflection and an arching logarithmic shade gave Poul Henningsen the possibility of controlling the fixture’s glare and shadows, since each shade evenly reduces the amount of radiant light due to their distance from the light source.

The PH 3-2½ Bollard is a member of the PH 3-lampshade family, and the principle behind the PH 3-shade system was established through the course of a couple of hectic months in the winter of 1925-1926 for an exhibition at Forum in Copenhagen.

This is what Poul Henningsen has to say about this new system in 1926: “The true innovation in the PH system is to create light that is both free of glare and economical. It is easy enough to create a glare-free lampshade system (indirect and heavily shaded light) if you’re willing to waste some of the light, and it is relatively easy to create a system that is extremely effective if you ignore the fact that it is extremely irritating to the eye (strong glare, etc.), but it is an art to create light that is both economical and glare-free.”