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 metal and painted white to ensure uniform, comfortable light distribution. Poul Henningsen designed the three-shade system during 1925/1926. The first lights using the system were designed for an exhibition in Paris. His work with Louis Poulsen continued until his death in 1967. Throughout his life, PH sought to create glare-free lighting; aiming to direct light where it was most needed, and creating soft shadows while using incandescent bulbs as a light source. The PH 4/3 Metal Pendant was launched in 1966. Its design follows the general three-shade system based on the logarithmic spiral, with the center of the light source positioned at the axis of the spiral. This light is a simplification of the light PH designed in 1929, winning him the highest distinction at the world exhibition in Barcelona at that time. Metal pendants were produced in a number of formats and colors, and the underside of the shade was painted white to provide diffuse light. To achieve warmer lighting, metal pendants were also produced with a gold-coated underside. Metal pendants have been produced in a number of sizes and colors over the years.