What is CRI?

CRI stands for Color Rendering Index. It is a number (0-100) that tells you how accurately a light source shows the true colors of objects compared to natural sunlight.

Let's break it down

  • Color Rendering: How well a light lets you see the real colors of things.
  • Index: A score or rating.
  • 0-100 scale: 0 means colors look very wrong, 100 means they look just like they would under daylight.
  • Natural sunlight: The reference point because it shows colors most naturally.

Why does it matter?

If the light you use has a low CRI, colors can look washed out or misleading, which can affect tasks like picking clothes, cooking food, doing art, or diagnosing medical conditions. A high CRI helps you see true colors, making everyday activities more comfortable and accurate.

Where is it used?

  • Home lighting: living rooms, kitchens, and bedrooms where you want colors to look natural.
  • Retail stores: clothing and cosmetics shops use high-CRI lights so products appear true to color.
  • Photography and video studios: accurate color rendering is essential for consistent images.
  • Healthcare: operating rooms and diagnostic labs need high CRI lighting to see subtle color differences in tissues.

Good things about it

  • Provides a simple, single number to compare different light sources.
  • Helps consumers choose lighting that makes spaces feel more natural.
  • Improves visual comfort and reduces eye strain.
  • Enhances color-critical tasks in professional settings.
  • Encourages manufacturers to develop better, more accurate lighting technologies.

Not-so-good things

  • CRI does not account for how bright or dim a light is; a high CRI lamp can still be too dim for a task.
  • It focuses only on the visible spectrum and ignores other factors like flicker or glare.
  • Some modern LEDs may score high on CRI but still render certain colors poorly; newer metrics (e.g., TM-30) can be more reliable.
  • The test method is based on a limited set of color samples, so it may not reflect all real-world colors.