What is color rendition (CRI) or visual acuity, and why is it important when discussing lighting options?
The lighting effect of different kinds of lights may be due to more factors than the foot candles produced (1). “Visibility, task, performance, mood and atmosphere, visual comfort, aesthetic discrimination, health, safety and well being, and social communication are all human needs served by light” (2). The color of the light can have a great impact on how much light is necessary and the additional effects resulting from lighting. A light meter can read the intensity of a lamp light in foot candles or lux, but it cannot measure clarity of vision as a result of using colored or non white light. This is an important consideration because LED lights are considered Spectrally Enhanced Lighting (SEL). Such SEL sources appear brighter because of their color characteristics but may not measure [photometrically] as bright (2). Evidence from studies have shown that when color temperature is cut in half (CCL 7500 to CCL 3500 it takes 4 times the foot candles to get the same functional light. The
