PH 4½-4 opal glass pendant lamp from Louis Poulsen is both a classic and modern ceiling lamp that fits perfectly, for example, above the dining room table. The shades are made of reflective mouth-blown opal glass in three layers that direct most of the light downwards. They are glossy on the outside and have a matte sandblasted inside that provides a soft and diffuse light. The iconic three-shade system was designed by Danish Poul Henningsen, who in collaboration with Louis Poulsen designed the first PH lamps in 1925-1926 for an exhibition in Paris. Here, he has used a scientific perspective as the lamp is constructed based on the logarithmic spiral, a mathematical spiral curve that occurs in many places in nature. This provides an even distribution across the entire curve of the shade and, together with the diffuse reflection through the glass, creates a harmonious and glare-free light. The numbers on the PH lamps refer to the size of the shades, and the letters come from the designer's initials. Feel free to explore the wide range of PH lamps.