Originally Posted by ronspradley
Where do I get access to a meter that will measure lumens in my existing lights? I need bright lights for reading.
Do you need lumens? Light meters that measure in foot candles have been around forever, should be able to pick a used one at a reasonable price.
Guide lines for using foot candles:
Casual reading 20 to 50 foot candles roughly 215 to 540 lumens/m2, or 2314 to 5813 lux.
Intense reading (studying or for those of us with old eyes) 50 to 100 foot candles or roughly 540 to 1080 lumens/m2, or 5813 to 11,625 lux.
The light meter needs to be capable of measuring light in the range that the human eye sees which is 500 to 600 nanometers.
We have always had the best results with Spectronics and Labino light meters. If accuracy is not a huge issue you can find off brands on ebay for under $75.00, saw one for $23.00 (measures in Lux). http://www.ebay.com/itm/100-000-Lux-...ht_4735wt_1187
Although converting Lux to Lumens is controversial at best (for the purists) there are a few web sites that have converters. I included the lux numbers above.
Place the light meter where you will be holding the book. You may see in the instructions for some light meters to measure intensity at 12 or 18" form the face of the light source. These distances are for complying with codes for performing inspection activities, a common use for white light meters.
As you search for light meters you may also want to use the terms radiometers and photometers. Be careful in searching that you don't buy a photography light meter. It would do a fine job of giving you f/stop and shutter speed but not much else.
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