Light Source |
Typical CRI Value |
| Incandescent/Halogen | 95-100 (by definition) |
| Fluorescent | 75-85 |
| Metal Halide | 65-85 |
| High-Pressure Sodium(standard) | 25 |
| Low-Pressure Sodium | 0-18 |
| Nichia WHITE LED | 85 |
| LumiLed Luxeon Star White LED | 65 (current) 85 (Summer '02) |
CRIs in the range of 75-100 are considered excellent; 65-75 is good, 55-65 is fair, and 0-55 is poor.
The Color Rendering Index, or CRI , of a source indicates how well it renders eight standard colors compared to a perfect reference lamp of the same color temperature. The comparison is only valid for lamps of the same color temperature. The CRI Index ranges from 1 to 100. A lamp with a CRI of 80 will render colors better than a lamp with a CRI of 50.
Although a CRI is a good measure when comparing two lights of the same color temperature, it does not necessarily make sense when comparing lights of different color temperatures. A very yellow incandescent (low color temperature) will have a CRI of 100 (by definition), even though a much better looking flourescent (6500K) may only have a CRI of 85.
