Color Rendering Index (CRI)

cri is important criteria of light quality

Color Rendering Index (CRI) is a measure of the quality of color light. To help determine how well lights reproduce color, bulbs are given a CRI score between zero and 100. This score represents a comparison between the spectrum of colors the light produces and the spectrum naturally produced by the sun in the same color temperature. For example, if a light receives a CRI score of 90, this means that the bulb is replicating 90% of the color spectrum the sun would naturally produce at the same temperature. In houses and work places, light sources with a high CRI give ‘true’ color which is important for safety and wellness.

typical cri in different scenarios

The followings are typical CRI values and color temperature for commonly used light sources:

• Candle: 1700k 100 CRI

• High Pressure Sodium: 2100k 25 CRI

• Incandescent: 2700k 100 CRI

• Tungsten Halogen: 3200k 95 CRI

• Cool White: 4200k 62 CRI

• Clear Metal Halide: 5500k 60 CRI

• Natural Sunlight: 5000-6000k 100 CRI

• Daylight Bulb: 6400k 80 CRI

• T8 Linear Fluorescent: 75 – 85 CRI

For the reason that most white light of LEDs are made by the combination of blue light generated by LED chip and the yellow phosphor, so the CRI is mainly up to the wavelength of the chip and the phosphor’s performance and quality. Due to the phosphor’s performance will be affected by the high temperature, to improve the CRI of LED products, iLUXZ use the high quality phosphor, which has good adaptability to high temperature. Besides, our experts have worked on optimizing the design of the light fixture thermal management to avoid the high operating temperature in the LED chips. The CRI can also be increased by supplementing the red or amber light, however, due to different wavelengths of chips have the different operating voltage and current, the electrical design will be very complicated, so this method is not widely used in practice.

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