**Subject:** Measuring UV

From: Kilian Anheuser <*kilian.anheuser*>

Date: Monday, September 4, 2006

Date: Monday, September 4, 2006

Carlyn Hammons <carlyn.hammons [at] thc__state__tx__us> writes >... I am in search for some obscure information and hope >that someone here might be able to help. I know that there is a >very complicated formula for determining microwatts per lumen using >the combination of a lux meter and a UV meter which gives readings >in microwatts per square centimeter. Does anyone recall this >formula? This is how you get there: 1 lux = 1 lumen per square m (by definition) 1 square m = 10,000 square cm Therefore: 1 microWatt per square cm = 0.0001 microWatt per square m = 0.0001 microWatt / lux per lumen This gives you: 1 microWatt per lumen = 10,000 microWatt per square cm and lux So, what you need to do is: Take your UV meter reading in microWatt per square cm Multiply by 10,000 Divide by your luxmeter reading (in lux) Now you have your microWatts per lumen Example: Your UV meter reading is 0.3 microWatts per square cm At the same time and in the same place you measure 50 lux Calculate: 0.3 x 10'000 / 50 = 60 This is a reading of 60 microWatts per lumen Good luck, Kilian Anheuser Conservateur responsable du secteur Laboratoire, ateliers de restauration et conservation preventive Musee d'art et d'histoire Rue Charles-Galland 2 Case postale 3432 1211 Geneve 3 Suisse +41 22 418 2520, Fax: +41 22 418 2511 *** Conservation DistList Instance 20:13 Distributed: Friday, September 8, 2006 Message Id: cdl-20-13-006 ***Received on Monday, 4 September, 2006