Lighting Technologies, Principle, And Measurement

Since long ago, man has compared colors by arranging objects side-by-side and looking at them under natural light (sunlight). Although torches, candles, incandescent lamps and other light sources are also used for illumination, it has always been the standard practice to compare colors under natural light.

In addition to fluorescent lamps, LEDs (light emitting diodes) have recently been adopted as illuminating lamps. When comparing how objects look under these new types of lamps against how they look under natural light, how closely they match is called the “color-rendering property.” A lamp that produces a hue similar to that of natural light is said to have a good (high) color-rendering property.

Today, appliance stores offer many types of lamps (incandescent, fluorescent, LED, etc). Further, fluorescent lamps and LED lamps come in tones like “white,” “warm white,” etc.

In the examples here, we illuminated an object with a D50 fluorescent lamp with good color-rendering property, a fluorescent lamp that was labeled as “Natural white” and an LED lamp.