[solarmeter®]

FYI: The prototype Model 9.6 Solarmeter used a slightly different Schott cutoff filter. It read about 10% lower than the final NIST traceable version. ALL of them (only about 5 units) have since been updated to the current sensor calibration.

Anyway... a reading of 10 on the prototype would read 11 on the production meter. Red (633-ish) fluorescent lamps still read only 10-15 mW/cm² - so obviously LEDs are (so far) a much better choice.... up in the 75-115 range.

Hey Todd..... I did not take any of your posts "the wrong way". I was just responding to the technical details you and/or Roy brought up. No offense taken at all.... I respond to any and all UV meter issues in like manner - always have, always will. "Accuracy" is my Geek middle name.

This whole Red (and Blue - Model 9.4) light metrics is a relatively new arena. NO other meter company (that I know of) makes these kind of meters.... so they will take some getting used to as the visible light phototherapy industry matures. Someday they will become the handheld radiometer "gold standard" like the UV Solarmeters already have. No hurry. I can wait. Too busy making tons of new Model 7.5's for Europe... where they are becoming "all the rage" for the new 0.30 W/m² Eeff irradiance dose-rate limit-cap.