The PH 5 is named after its top shade, which is 50 cm in diameter, while the PH 4 series (like PH 4/3 or PH 4½–3½) refers to specific proportions between its shades—often indicating smaller or more compact designs. Shade Structure: Both use Henningsen’s multi-shade system to reduce glare, but the PH 5 typically has more layers and a more complex build, including color-treated inner reflectors (red and blue in early models) for warmer light. The PH 4 versions often have fewer shades and a simpler, lighter appearance. Lighting Purpose: The PH 5 is designed for broad, even light distribution—ideal over dining tables or large areas. The PH 4 series generally provides more concentrated light, better for task lighting or smaller spaces. Mounting Options: PH 5 is typically a pendant lamp, while the PH 4 design has more diverse applications—available as pendants, table lamps, floor lamps, and wall sconces. Design Details: The PH 5 often includes a distinctive colored anti-glare disc underneath, while the PH 4 models keep a more minimal look.

Over time, subtle changes have been made to its construction: older models feature a metal bottom plate secured with a slotted screw, whereas newer versions use a glass plate held by clamps. Additionally, the original lamps had simple metal stickers inside, often etched or stamped, while modern versions use printed adhesive labels. Despite these updates, the PH 5 remains true to Henningsen’s vision of glare-free, functional beauty.