Color rendering index facts for kids

You can see the CRI number printed on a light bulb's box (often under "Color Accuracy").

If you shine a lamp through a prism and see a smooth rainbow, the lamp's CRI is likely high.

The Color Rendering Index (CRI) is a special number. It tells you how well a light bulb or lamp makes colors look. You can often find this number on the light bulb's box.

The CRI number can be anywhere from 0 to 100. Sometimes, it can even be less than 0. A high CRI number, like 80 or more, means colors will look natural and true. A low CRI number means colors might look strange or fake.

What CRI Tells You About Colors

A high CRI number is great, but there's a catch! It only guarantees correct colors if the light itself is white. This is because of how scientists test CRI.

For example, candles and old-fashioned incandescent light bulbs have a CRI of 100. But their light is warm and yellowish, not truly white. So, even with a perfect CRI, they won't show all colors exactly as they are.

CRI in Everyday Life

The CRI of natural daylight at noon is 100. This is because our eyes are used to seeing colors under natural sunlight.

Modern lights like good fluorescent tubes or LED lamps usually have a CRI of 80 or higher. Lights with a CRI of 80 or more are perfect for homes and offices. They help everything look clear and vibrant.

Some lights have a very low CRI. For instance, orange sodium vapor lamps have a CRI lower than 0. That's why they are mostly used as streetlamps. They are good for seeing shapes at night, but not for seeing true colors.

Related pages

• Color temperature
• Spectrum

Images for kids

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  This chart shows different light colors and how they are measured.

See also

In Spanish: Índice de reproducción cromática para niños