Dominant λ Light Spectrometer

In-app purchases
4.3
502 reviews
50K+
Downloads
Content rating
Everyone
Screenshot image
Screenshot image
Screenshot image
Screenshot image
Screenshot image
Screenshot image
Screenshot image
Screenshot image
Screenshot image
Screenshot image

About this app

This app gives you the possibility to very easily measure the dominant wavelength of different light sources.

The 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.

Measuring Light
• Find a white or gray surface (a plain piece of white paper works well).
• Point your camera at the surface, ensuring it is lit by only the light source you wish to measure.
• The app will display the dominant wavelength of the light in nanometers (nm), the frequency of the light in terahertz (THz) and the period length of the light in femtoseconds (fs).

Automatic Warnings
The app provides helpful warnings when the conditions are not ideal for accurate measurement, to help you get the best results.

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.

Please note that the smartphone cameras have limitations when it comes to distinguishing between different very short (UV, ultraviolet), or very long (IR, infrared) wavelengths. More specifically, on many devices the accuracy below 465 nm and above 610 nm is very limited. This is due to the physical camera sensors in the devices. An automatic warning appears on the screen for these short and long wavelengths.

The app now supports 40 different languages.

Free for a Limited Time
Enjoy full functionality for a few weeks. After that, choose a one-time fee or subscription.

Feedback
I value your feedback. Email me at apps@contechity.com with any suggestions.
Updated on
Oct 7, 2025

Data safety

Safety starts with understanding how developers collect and share your data. Data privacy and security practices may vary based on your use, region, and age. The developer provided this information and may update it over time.
No data shared with third parties
Learn more about how developers declare sharing
This app may collect these data types
App activity
Data is encrypted in transit
You can request that data be deleted

Ratings and reviews

4.4
493 reviews
Vincent Koehler
May 10, 2025
I love this tool alot! This is the only application available for this purpose! But, two things. I would like it to tell the specific frequency and wavelength of the Infared Radiation (IR) that I'm trying to messure since cameras are usually able to take in IR. I'm not the biggest fan of it saying "IR or Red 700-800 Nanometers (nm)". And lastly, after the first time I use this, It will start forcing me to buy the subscription thing in order to use it which bothers me.
5 people found this review helpful
Did you find this helpful?
Contechity AB
May 11, 2025
Thanks a lot for your review! I also wish that it was possible to distinguish between different wavelengths in the Near IR range. The smartphone cameras see these wavelengths, but they all appear the same to it, so it is unfortunately not possible for an app to tell them apart. Yes, it is free for a few weeks. Thank you! apps@contechity.com
Infraguy
November 18, 2025
You can use it for free for a day or two and you will see that it measures 575nm even when there is only 620nm and 535nm in the light source, no 575nm.It measures very inaccurately and has nothing to do with reality, which is orange and sometimes says 660nm. It says infrared for purple things. Then it asks you to pay for it, you can't do anything and you have to pay to continue using it. It's a scam, good for gaming but very bad at measuring.
Did you find this helpful?
Contechity AB
November 26, 2025
It is free to use for a few weeks. What is measures is the Dominant Wavelength, which actually can be 575 nm even if the light only has the two wavelengths 535 nm and 620 nm. Feel free to contact me directly at apps@contechity.com if you want a longer explanation on how it works. Thank you!
Shyam Shyam
November 2, 2025
the app work's fine but there's no way to confirm that the reading are correct.. so it's just that this helps to see spectrum of light visible under different lighting conditions
Did you find this helpful?
Contechity AB
November 4, 2025
Thanks a lot for taking the time to leave a review! Is there anything in the app that can be improved to deserve a 5-star rating from you? Thanks again!