RE: intensity of bulbs
Wooops! You're right of course - wattage is total output not per foot as I was thinking. Geoff Chaplin ジェフ チャップリン geoff@geoffgallery.net www.geoffgallery.net Skype: geoffchaplin1611 UK mobile (英国の携帯電話): +44(0) 7770 787069 Japan mobile (日本の携帯電話): +81(0) 90 6440 7037 Japan land line / fax (日本の電話とファクス): +81(0) 166 92 5855 -----Original Message----- From: etienne garbaux [mailto:photographeur@nerdshack.com] Sent: 24 February 2009 13:37 To: alt-photo-process-l@usask.ca Subject: Re: intensity of bulbs Barry wrote: >Does a 24" bulb at 20 watts have the same intensity as a 48" bulb at 40 watts? I would expect them to have the same intensity per unit surface area, so used in a light box they should give equal exposures (but you could do two prints at a time in the 48" unit because its total output is double). This is confirmed to a first approximation by looking at otherwise-identical 24" and 48" tubes -- which you can often do in the lighting aisle of your local home improvement store. Their surfaces appear to be the same brightness. (No reason I can see why the same should not be true for actinic phosphors.) If you Google for tube specs, you can probably find more precise information. Best regards, etienne
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