Warm and Cold Cities: The Orange of Sodium Lamps and the White of LEDs

A night view of a city block where streetlights are being replaced, with two types of light coexisting in the scene: the yet-to-be-replaced high-pressure sodium lamps emit a low color temperature orange-yellow light, which is dense in color, has poor color rendering, and makes all illuminated vehicles and clothing appear brownish-yellow, with soft-edged light spots; the newly replaced LED streetlights emit a 4000K neutral white light, which accurately restores colors, making red and blue car bodies clearly discernible, with sharp-edged and well-defined light spots. The two types of light meet in the middle of the street, creating an orange and white transition zone on the ground, where the colors are most muddled. Pedestrians on the sidewalk are simultaneously illuminated by both types of light. Avoid: making the two types of light look identical, eliminating the transition zone, unifying the entire street to a single color temperature, adding other colored light sources.

Translated from Chinese by AI.

一個正在更換路燈的城市街區夜景,畫面中同時存在兩種光:尚未更換的高壓鈉燈發出低色溫的橘黃光,顏色濃重、演色性差,照到的車輛與衣物顏色全部偏向褐黃,光斑邊緣柔和;已更換的 LED 路燈發出 4000K 的中性白光,顏色還原正確,紅色與藍色的車身清楚可辨,光斑邊緣銳利、範圍明確。兩種光在街道中段交會,地面出現橘與白的交界帶,交界處的顏色最為混濁。人行道上的行人身上同時被兩種光照到。避免:讓兩種光看起來一樣、消除交界帶、把整條街統一成單一色溫、加入其他彩色光源。