Peak Wavelength vs. Dominant Wavelength in LED selection

When choosing between our LED products, there are two different wavelength parameters: “Peak Wavelength” and “Dominant Wavelength” A common question is “What is the difference between them?”.


Peak Wavelength - Peak wavelength is defined as the single wavelength where the radiometric emission spectrum of the light source reaches its maximum. More simply, it does not represent any perceived emission of the light source by the human eye, but rather by photo-detectors.

Dominant Wavelength - Dominant wavelength is defined as the single wavelength that is perceived by the human eye. Generally one light source consists of multiple wavelength spectrums from the light source rather than one single wavelength. Our brains turn those multiple spectrums into a single color of light consistent with a single specific wavelength which is what we see when we look at the light. That’s the light source’s Dominant wavelength.

In general, these two parameters are not drastically different, but it can pay to consider our application when using these two parameters.

  • For example, if the LED is used in optical instruments and machines are being used to identify the wavelength, you should use Peak Wavelength for your LED selection.

  • If the LED is used to backlight a display or otherwise illuminate or indicate something for human operators, you should use Dominant Wavelength for your LED selection.

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