Dominant λ Light Spectrometer 4+

Measures Dominant Wavelength

Bjorn Folkstedt

    • 5.0 • 2 Ratings
    • Free
    • Offers In-App Purchases



Dominant Wavelength Light Spectrometer is a new app that gives you the possibility to very easily measure the dominant wavelength of light.

This app uses the advanced capabilities of your smartphone's camera sensor, combined with sophisticated algorithms, to as accurately as possible analyze the incoming light and determine its dominant wavelength. This technology opens up a world of possibilities, allowing you to delve into the intricate details of the light spectrum in our environment.

For light with only one wavelength, such as the light from a regular colored LED, the dominant wavelength corresponds to the wavelength of that light.

How to Measure
To measure the dominant wavelength of light, find a surface that is white or gray. A white piece of paper works perfectly. Just make sure to avoid any colors on the surface. Point the camera towards that surface. If you direct the camera of your device towards an even surface there shall be no warning text on the screen and the app will show the measured dominant wavelength of the light that falls on that surface. If you want to measure the dominant wavelength of a special light source, it is of utmost importance that you light the surface only by this light source and no surrounding light, as that would give a false measurement.

Automatic Warnings
The app tries to help you by displaying warnings on top of the camera preview screen when it suspects that the camera is not directed to an even white surface or that the light is not enough to make a reliable measurement.

What is Dominant Wavelength?
Dominant wavelength is a concept commonly used in the field of color science and perception. It refers to the wavelength of light that appears most prominent or dominant in a given color mixture or light source. In other words, it is the wavelength that our eyes perceive as the primary color in a mixture of different wavelengths. If the light only has one wavelength, such as the light from a regular colored light emitting diode, LED, the dominant wavelength will of course correspond to the wavelength of that light source.

How Accurate are the Measurements?
To measure the dominant wavelength of light accurately is more complex than it might appear. On a smartphone or tablet it is complicated further by the fact that all devices are different from each other. See the measurements as god approximations. Make sure that you always use a white surface and that only the light that you want to measure hits that surface. Also, avoid any shadows or reflections from your hands or your device. If you do that, the measurements shall be fairly good estimations. And for relative measurements, i.e. comparing the dominant wavelength between different light sources, with the same smartphone or tablet, the measurements shall be good if the conditions above are met.

Privacy Policy,
End User License Agreement,

This is a new app and any feedback is greatly appreciated. I try to answer all emails.

What’s New

Version 1.0.7

• Misc minor improvements
Do you have any suggestions? Contact me at
If you like the app, make sure you rate and review it here on App Store - it helps others find the app and it gives me incentive to develop it further. Thanks!

Ratings and Reviews

5.0 out of 5
2 Ratings

2 Ratings

App Privacy

The developer, Bjorn Folkstedt, indicated that the app’s privacy practices may include handling of data as described below. For more information, see the developer’s privacy policy.

Data Not Linked to You

The following data may be collected but it is not linked to your identity:

  • Purchases
  • Identifiers
  • Usage Data

Privacy practices may vary, for example, based on the features you use or your age. Learn More

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