PrismMeter: Light Meter & CCT

Is this bulb really 2700K? Is your monitor flickering? PrismMeter turns your Android phone into a practical light meter and pocket spectrometer: measure color temperature (CCT) in kelvin, ambient lux, flicker and an estimated visible spectrum, live, using the camera and the ambient-light sensor.

MEASURE AND UNDERSTAND
- Color temperature (CCT) in kelvin, with chromaticity (CIE xy) and Duv
- Lux meter using your phone's ambient-light sensor, with a camera-based estimate as a backup
- Estimated visible spectrum from 400 to 700 nm: a spectrometer view of the light around you
- Relative blue-light index for evening and night lighting
- Flicker modulation and frequency where your device supports it: detect LED flicker
- Estimated light-source classification (daylight, screen, lamp and more)

MADE FOR REAL LIFE
- Photography and video: check white balance and light color before you shoot
- Home and office: compare bulbs and LED panels before you buy or replace them
- Plants and aquariums: check grow-light and aquarium spectra
- Visual comfort: detect harsh flicker and strong blue light in your workspace
- Curious minds: explore spectroscopy with a pocket light lab

An essential tool for photographers, videographers, lighting designers and the simply curious.

SAVE, COMPARE, EXPORT
- Keep a history of your measurements
- Compare two light sources side by side
- Calibrate against a trusted reference for more consistent results
- Export as PDF, CSV, JSON or a shareable image

SCIENTIFIC HONESTY, BUILT IN
Every metric is labelled SENSOR (direct hardware reading), CALCULATED (derived from readings) or ESTIMATED (heuristic reconstruction with explicit uncertainty). PrismMeter shows confidence and device limits instead of claiming laboratory precision: your phone's camera is not a certified lab spectrometer, and the app never pretends it is.

PRIVACY FIRST
- Measurements are processed and stored locally on your device
- No account, no sign-up
- Core measurement features work offline
- The camera permission is used only for light analysis

PrismMeter is free with ads. You can remove ads anytime with a single lifetime purchase.