The City Changed Its Bulbs: Night Went from Orange to White

A sodium lamp emits at essentially one wavelength, a narrow yellow around 589 nanometres, which is why a red car and a green car parked under it look like two shades of the same brown. Photographs from those years carry a colour cast no white balance ever fully removed, because there was nothing else in the light to balance against. Cities liked the lamps for their efficiency and their reach through fog, and nobody had to think about the picture they were making.

The replacement runs at four thousand kelvin with a broad spectrum, so the same two cars are red and green again, brick reads warm, leaves read as leaves. What arrives with that honesty is contrast: LED optics cut a sharp pool of light and let the space beyond it drop away, so a street that used to be evenly amber now alternates between lit and genuinely dark. Windows above the road stopped competing with the glow and became legible.

For night pictures this changed the working method more than the exposure. White light lets you keep the colour you saw, but it punishes a long shutter, since the bright pools blow out while the gaps stay empty, and the old trick of leaving everything orange no longer holds the frame together. On a screen the difference is easy to spot: an amber street reads as memory, a white one reads as tonight, and the same corner belongs to two different decades depending on which lamp was in it.