Which light source has a CRI of 100?

Which light source has a CRI of 100?

• A. Daylight
• B. Incandescent
• C. LED
• D. High Pressure Sodium

Answer: (A)

Color Rendering Index (CRI) measures how faithfully a light source reveals colors compared with a reference. A score of 100 means colors appear exactly as they would under the reference light. Daylight is the standard reference for CRI and is defined to have perfect color fidelity, so its CRI is 100. That’s why daylight is the best answer here. Other sources have spectra that distort colors: high‑pressure sodium emits a narrow spectrum, yielding a low CRI; LEDs vary widely in spectral content and can be lower than daylight; incandescent lights have a broad spectrum and typically render colors well, but the reference standard assigns the 100 value to daylight.

Color Rendering Index (CRI) measures how faithfully a light source reveals colors compared with a reference. A score of 100 means colors appear exactly as they would under the reference light. Daylight is the standard reference for CRI and is defined to have perfect color fidelity, so its CRI is 100. That’s why daylight is the best answer here. Other sources have spectra that distort colors: high‑pressure sodium emits a narrow spectrum, yielding a low CRI; LEDs vary widely in spectral content and can be lower than daylight; incandescent lights have a broad spectrum and typically render colors well, but the reference standard assigns the 100 value to daylight.