Meter needs to be able to be used with basic instruction by person not necessarily skilled in the dark arts or, at least not in these ones. ie commercial lux meter aimed at insolation or general light level measurements. Anything sold as a "lux meter" with 100,000 lux + capability is very liable to be OK. Russell --=20 http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist .