Introducing f.luxometer®

One tool to measure screens, lights, and eyewear

If you want to measure how light can affect circadian rhythms, alertness, and mood, it’s best to use a spectrometer. To get results that you can see right away (and show to other other people), you need software that is designed for non-visual responses.

Melanopic measurements made easy, and more

With f.luxometer®, you can measure light spectra with a portable meter and see circadian quantities like melanopic irradiance (or melanopic lux) and M/P ratio instantly. Save the raw data and analyze it however you like. Or, when you want to, share your results online, in just one click.

Using the f.luxometer® software with x-rite’s hardware, there’s now a low-cost way to look at the spectrum a light makes.

A tablet PC measuring light with x-rite spectrometer and f.luxometer® software

i1Studio from x-rite

The meter we recommend is the i1Studio spectrometer from x-rite. This meter connects to your laptop via USB, and on its own, it’s great at calibrating your screen and measuring the reflectance of surfaces. It’s also a bargain for doing these kinds of measurements: a reference meter can cost $10,000, but this one gets awfully close for a lot less money.

1. Purchase a meter

If that's not available, you can get the older model here.

International customers: please look for EOSTUDIO or CMUNPH resellers in your local market.

2. Purchase a f.luxometer license

The f.luxometer system allows you to measure light and output the raw spectral data. It automatically computes circadian metrics as you measure (like Melanopic irradiance and M/P ratio). If you want to, you can easily share measurements via our cloud service.

This version is priced at $99 a year, which includes updates and as much cloud storage as you need. It's intended for one person to use on a couple machines, or for one meter on a shared machine.

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Features (and Metrics)

  • Melanopic quantitites (equivalent lux)
  • CCT (color temperature), lux, and cd/m²
  • Transmission measurement (for measuring filters and eyewear)
  • Lucas photoreceptor responses for circadian research (all major photoreceptor responses that affect the ipRGCs)
  • Spectral irradiance measurement (for general lighting, in uW/cm²/nm)
  • Spot radiance measurement (from a screen or 10 degree patch, in uW/²/sr/nm)
  • Saving data to the f.luxometer cloud service, with more analysis there, including advanced color metrics
  • Optional saving of geo-location (e.g., to identify multiple buildings)
  • Saving measurements to disk as CSV

Cloud-only features

  • Ability to share and download measurements
  • Color-related metrics including CRI, 10-degree observer, and CIE PO06
  • Blue Light Hazard (IEC62471)
  • PAR and some wildlife responses
  • Several additional proposed circadian metrics
  • Ability to view time-series measurements
  • Capture can be done without a connection, and uploaded later

System Requirements

  • macOS 10.8+ or Windows 7+ (Windows 8 for geo-location)
  • Internet connection to activate and setup
  • English language only

i1Studio/Colormunki capabilities

  • 5 lux to 50,000 lux (ambient light)
  • 0.2 cd/m2 to 1200 cd/m²
  • CCT within about 300K
  • x, y repeatability: ±0.002
  • Fast measurement, 1.5 seconds per sample

Mobile use

  • f.luxometer works well with Windows tablets like the Microsoft Surface.
  • Inexpensive Windows 10 tablets (<$200) are available and are excellent for mobile use or remote monitoring of a building.

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