A clear definition of lumens can be found in this publication: 'The Museum
Environment' by Garry Thomson (Ed. Butterworth-Heinemann).  You may want to
check page 20.
To reassume:
(Imperial system)       1 footcandle = 1 lumen/square foot
(Metric system) 1 lux    = 1 lumen/square metre
                        1 footcandle = 10 lux                   = 10 lumens

                        1 lux    = 1/10 footcandle      = 1/10 lumens/square
foot
Confusing as it may look, it is pretty easy.
Good luck.

Flavia Perugini, conservator
George Washington's Mount Vernon
P.O. Box 110
Mount Vernon, VA 22121-0110
Tel. (703) 799-8632
Fax (703) 799 8698
[log in to unmask]
www.mountvernon.org


-----Original Message-----
From: Anne Lane [mailto:[log in to unmask]]
Sent: Thursday, November 01, 2001 12:35 PM
To: [log in to unmask]
Subject: Lumens


Hi, folks - a lighting question here. Lumens are looming large on my
horizons right now. Any of the recommendations I have read for exhibit
light levels have been expressed in either lux or footcandles, easily
convertible one to the other. I am now the proud owner of a fleet of Hobo
dataloggers which express light levels in lumens per square foot. While
they gave me plenty of ammunition for the choice of 50-watt incandescent
spots over 50-watt halogens for lighting sensitive paintings in a gallery,
I don't really know how to use the readings to make judgements where a
simple either-or choice does not exist. Can anyone give me guidance here?
Or point me to appropriate literature?
Thanks,
Anne

=========================================================
Important Subscriber Information:

The Museum-L FAQ file is located at
http://www.finalchapter.com/museum-l-faq/ . You may obtain detailed
information about the listserv commands by sending a one line e-mail message
to [log in to unmask] . The body of the message should read "help"
(without the quotes).

If you decide to leave Museum-L, please send a one line e-mail message to
[log in to unmask] . The body of the message should read "Signoff
Museum-L" (without the quotes).

=========================================================
Important Subscriber Information:

The Museum-L FAQ file is located at http://www.finalchapter.com/museum-l-faq/ . You may obtain detailed information about the listserv commands by sending a one line e-mail message to [log in to unmask] . The body of the message should read "help" (without the quotes).

If you decide to leave Museum-L, please send a one line e-mail message to [log in to unmask] . The body of the message should read "Signoff Museum-L" (without the quotes).