克鲁伊特霍夫曲线

Arie Andries Kruithof conducted experiments in 1941 where observers were asked to evaluate the appearance of a room lit by discharge lamps of varying color temperatures and illuminance levels. By plotting the combinations that were rated as ‘pleasing’ or ‘natural’, he defined a bounded region on a graph with illuminance on the y-axis and color temperature on the x-axis. For example, a dim light (e.g., 20 lux) was found pleasing only if it had a very warm color temperature (e.g., 2000 K), similar to candlelight. A bright light (e.g., 500 lux) was pleasing only if it had a cooler temperature (e.g., 4000 K or higher), similar to daylight.

虽然最初的实验样本量较小，且其严格有效性也存在争议，但克鲁伊特霍夫曲线所描述的普遍原理却影响深远。它为照明设计提供了一个简单直观且符合人类体验的指导原则：温暖昏暗的炉火光线令人感到舒适，而凉爽明亮的天空光线则令人精神焕发。这一概念是现代以人为本、遵循昼夜节律的照明系统的基础，旨在通过调节全天的光强度和色温来改善健康和舒适度。