Why T8s are brighter than T12s

> From: "ian (i.b.) philips" <ianphil at bnr_ca>
> Date: Wed, 6 Dec 1995 11:54:00 -0500
> Subject: Article on Fluorescent Lamps and Ballasts
> In the meantime, the editor had a question: "Why are T
> lamps brighter than equivalent T12s?". This assumes that one alr
> accepts that they are (is this generally accepted?). Can anyone
> out here?

The brightness and quality of light from a fluorescent is based largely on
the ballast that controls it and the phosphors that line the inside of the

I know T8s put out more lumens per watt (greater efficacy) than T12s.
Offhand, I don't know how they compare watt for watt. Another reason T8s
have greater efficacy is that they are thinner. In a multiple lamp fixture,
the tubes don't "block" each other's light as much.

Greg. Tong
San Francisco, CA, USA
gtong at sirius_com

"Every infinity is composed of only two halves."