Illuminating the Technical Terms of Lighting

Welcome to another enlightening journey where we simplify the world of lighting. Today, our focus on ‘Understanding Lighting Terms’ will illuminate the mystifying language often encountered in the industry. Lumens, Kelvin, CRI, foot-candles, and more – we’re all set to demystify these terms to help enhance your understanding and communication of your lighting requirements. So, let’s get started!


Kelvin (K) is a unit that describes the color temperature of a light source. Lower Kelvin values (e.g., 2000-3000K) produce a warm, yellowish light, similar to a candle or sunset. Higher Kelvin values (e.g., 5000-6500K) emit a cool, bluish light, akin to daylight. Choosing the right color temperature can drastically affect the mood and functionality of your space.


Lumens are the unit of measurement for brightness in a light source, in other words, the amount of light emitted per second. Unlike wattage, which measures energy use, lumens measure luminous flux, a fancy term for the total quantity of visible light emitted by a source. The higher the lumen rating, the brighter the light source.

Lumens = Light Output

CRI (Color Rendering Index)

The Color Rendering Index is a scale from 0 to 100 percent indicating how accurate a given light source is at rendering color. In simpler terms, it shows how “true” colors will look under a particular light. A CRI of 80-100 is considered excellent and will show colors most realistically.

CRI Scale


In our quest for understanding lighting terms, we come across the concept of ‘foot-candles’. This term refers to the measurement of light intensity received by a surface. Specifically, a foot-candle is the unit of illumination that a one-foot-radius sphere would obtain from a single candle positioned at its center.

Foot Candle Conversion chart

LED (Light Emitting Diode)

LEDs are energy-efficient, durable light sources which use semiconductors and electroluminescence to create light. LED lights use less energy than traditional bulbs and have a much longer lifespan, making them a sustainable choice for long-term lighting.

IP Rating (Ingress Protection Rating)

The IP rating system classifies protection against dust, water, and accidental contact in electrical devices. An IP65-rated outdoor light fixture is dustproof and protected against nozzle-projected water.

Check out one of our previous blogs for a more in depth explaination of an IP rating here

A chart that explains IP ratings


Understanding Lighting Terms can seem complex, but once you understand these technical terms, it becomes far more accessible and intriguing. Whether you are designing the lighting layout for a new project, replacing your current lights, or simply interested in the science behind your everyday environments, understanding these concepts can significantly enhance your ability to make informed decisions.

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