Color Temperature Meter+

Color Temperature Meter+ measures the colour temperature of the light around you in Kelvin, with tint, mired and the camera white balance to match, straight from your iPhone's camera.

▶ HOW IT MEASURES
On iPhone the app reads the camera's own estimate of the light falling on the scene, the same estimate iOS uses to set white balance. Point the camera at a plain white or grey surface lit by the light you want to measure, not at the lamp itself. The reading settles within seconds and shows a ± range, so you can see how steady it is. When that estimate is not available, the app samples the centre of the frame instead, and you can calibrate it once on white paper in daylight.

▶ WHAT YOU SEE
• Kelvin with a ± range, updating live
• Mired value for filter and gel maths
• Light type: golden hour, tungsten, fluorescent, LED, daylight, cloudy, shade
• Tint (green or magenta) and Duv
• Spectrum bar from 1,000 K to 15,000 K
• The nearest camera white-balance preset: tungsten, fluorescent, flash, daylight, cloudy or shade

▶ FREEZE AND SAVE
Tap Freeze to hold the current reading. A result card shows the Kelvin, mired, light type and matching white-balance preset, with Save Reading and Measure Again right below it. Saved readings keep their date and time. The latest 50 are kept, you can delete any of them, and you can export the list as CSV.

▶ PHOTOGRAPHY WB ASSIST
Pick a target of 3200 K, 4300 K, 5500 K or 6500 K. The app shows the mired shift from the measured light to that target, the Kelvin to dial into your camera's custom white balance, and the CTO or CTB gel strength that closes the gap, from 1/8 upwards.

▶ REFERENCE CHART
Thirteen common light sources, from candle flame (1,900 K) to clear blue sky (10,000 K), to compare with what you measured.

▶ HONEST LIMITS
A phone camera is not a spectrometer. The app reports correlated colour temperature and tint, which is what matters for matching white balance and choosing gels. It does not measure spectral power distribution, CRI or TLCI, and two lamps with the same colour temperature but different spectra read the same. Mixed lighting gives a blend of the sources. Use it to set up shoots, match bulbs and check rooms; use a dedicated colour meter for critical colour work.

▶ PRIVACY
Camera images are analysed on your device and are never uploaded.

Available in 30 languages.