Lumen: Light Meter

PIGMENT

About this app

Lumen is a professional-grade ambient light meter, photographic exposure calculator, and architectural lighting standards guide engineered entirely in pure native Java.

Whether you are evaluating desk illuminance in an office, ensuring adequate light for indoor plants, checking warehouse safety standards, or calculating exposure settings for medium-format film photography, Lumen delivers instantaneous, calibrated photometric readouts directly from your hardware sensor.

KEY FEATURES:

● ACCURATE PHOTOMETRIC ILLUMINANCE
- Real-time illuminance in Lux (lx) and Foot-candles (fc).
- Custom logarithmic arc gauge spanning 5 orders of magnitude (1 to 100,000 lux) with clear decade reference marks (1, 10, 100, 1k, 10k, 100k).
- Rolling statistics: Real-time Minimum, Average, and Maximum tracking.
- Reading freeze function (“Hold”) to lock values ​​in hard-to-reach spaces.
- Hardware ceiling detection with explicit “Sensor Capped” warnings for direct sunlight.

● 60-SECOND ROLLING AREA CHART & FLICKER ANALYSIS
- Smooth rolling area chart with target threshold line and real-time illuminance history.
- AC mains luminaire flicker detection (calculates percent ripple and 100 Hz / 120 Hz ballast frequency).
- 5-minute continuous sampling mode for ambient light stability audits.

● NORMATIVE LIGHTING STANDARDS CHECKER
- Preloaded with 16 international workplace and architectural lighting standards derived from CIE S 008/E-2001 and ISO 8995-1 / EN 12464-1.
- Workplace (Office Desk, CAD Workstations, Conference Rooms, Archives).
- Home (Kitchen Counter, Reading Nook, Bathroom Vanity, Living Area).
- Retail (Merchandise Displays, Supermarket Aisles, Fitting Rooms).
- Outdoor (Building Entrances, Covered Walkways, Parking Lots).
- Real-time comparison with colour-coded compliance verdicts (On target, Below minimum, Too bright) and acceptable range bracket visualization.

● PHOTOGRAPHIC EXPOSURE CALCULATOR
- Converts ambient lux directly into standard Exposure Values ​​(EV at ISO 100).
- Interactive exposure triad controls: Select ISO (50 to 6400) and Aperture (f/1.4 to f/22) to instantly calculate recommended shutter speeds (1/8000s up to 30s bulb).
- Quick equivalent exposure lookup table.
- Complete 5-column EV lookup reference from EV -2 (starlight) to EV 16 (bright snow).

● SENSOR CALIBRATION & ATMOSPHERIC THEMES
- Fine-tune phone sensor response against a laboratory photometer with precision calibration multipliers (0.20x to 5.00x).
- 8 high-resolution calibrated atmospheric themes (Warm Amber Dawn, Golden Twilight, Solarium Lux, Nordic Crisp, Tungsten Warmth, Luminescent Mint, Studio Neutral, High Noon Solar).

● ZERO PERMISSIONS & TOTAL PRIVACY
- Operates 100% offline.
- Exactly ZERO Android permissions required ( = 0).
- No GPS tracking, no microphone, no internet access, no advertisements, and no analytics SDKs.
- Export your full measurement history anytime as standard CSV.