On the press, a UV lamp that won’t strike isn’t just downtime. It’s scrap, rework, and a mad scramble to find the root cause. The trigger and the lamp are a matched system. If the open-circuit voltage, lead impedance, and ignitor energy profile don’t line up, the arc gets unstable. You end up with weak spectral output at 365nm, 385nm, or 405nm.
That shows up as undercured ink transfer, weak adhesion, and a cure window that keeps slipping. Here’s what actually matters. When you test a UV lamp, the meter has to measure what drives cross-linking: peak irradiance (mW/cm²) and curing energy density (mJ/cm²) across the wavelength band you care about. Use a broadband sensor with NIST-traceable calibration, and add a narrowband sensor to isolate the dominant emission line. Make sure the response time is fast enough to capture the start-up pulse shape, and confirm the dynamic range covers both the ramp-up and full operating output. Then lock down your geometry and track lamp warm-up drift, reflector efficiency, and dichroic coating degradation. The payoff is practical. When the trigger-and-lamp combo isn’t delivering the required dose, the meter turns a vague complaint into hard data. You can correlate ignitor energy, lamp electrode condition, and voltage drop with measured peak irradiance and dose at the substrate plane. That lets you tune the electrical setup, set a clear go/no-go threshold for lamp replacement, and stabilize cure windows across offset, flexo, and screen lines. Fewer strike failures, more consistent ink set, and predictable lamp life curves. A few things to keep straight. Matching triggers to lamps is application-specific. Distance, reflector geometry, and sensor alignment shift readings more than most operators expect, so fix the measurement position and stick to it. High-pressure mercury lamps hit hard in the UV-C range. Make sure your instrument’s filters and sensor material are rated for that spectrum, and use ozone-free quartz where you need it. For repeatable results, run the lamp to thermal equilibrium before you take the final intensity reading.