HIT: Overhead Projector Lumens

[Judy Meadows <psj000@MAIL.CONNECT.MORE.NET>]

Dear LM_Netters:

Here is what I was told concerning the amount of lumens necessary for an
overhead projector for ordinary classroom use:


Basically, the more lumens the brighter the image. If you will be using the
projector in a darkened room, then you can get my with a lower lumen number
than if you are using it in a typical classroom with a wall full of windows.

You mentioned that some had a open bulb and some an enclosed bulb. Did you
mean open or closed head? There really isn't much difference. A closed head
is the traditional triangular box, while the open head is simply a pop-up
mirror. The closed head probably stays cleaner inside, but is a pain to
clean when you finally have to do it. The open head is easier to clean, but
will probably need it more often.

Back to the lumens question. If you are planning on using the overhead with
an lcd panel and computer, you need to go with a very high number. I've
been quoted anywhere from 2500 to 4000 as the minimum. Again, the lighting
in the room will make a difference.

>Is 2300 lumens a resonable amount for use in a fairly light classroom?

I would say it is probably adequate for regular use, but not bright enough
to use with an LCD panel.

*******

If you want to use the overhead with an LCD you need the higher lumens with
a low heat lamp. We use Elmo HPL-355 with 80V 360W the enclosed lamp seems
to work for us. The arm is out of the way so the entire surface can be
used. Hope this is helpful.
__________________________
Judy L. Meadows
K-12 Librarian
Verona R-7 School District
101 E. Ella Street
Verona, Missouri  65769
psj000@mail.connect.more.net

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