In article , Bret Miller wrote:

A simple question from a simple mind. You have two lights, both
fluorescent and both 40 watts. On light is 36" long, the other is the
spiral type that fits in a regular incandescent socket. Do they both
give off the same amount of light?

Are you sure you have a 40 watt 36"? 40 watt is usually 48" and 30 watt
is usually 36".

Unlikely. A good 3-footer or 4-footer produces more light than a good
spiral of the same power consumption. However, if one is og good quality
and in good condition and at a favorable temperature and the other is not,
the better one may produce more light regardless of which is a 4-footer
and which is a spiral.

And, do different 40 watt 36" bulbs give off different amounts of
light, or does it just seem that way based on the "Temperature" of the
color?

Light varies with a number of factors:

1. Age, condition and actual temperature of the bulb

2. Quality and general type of the ballast of the ballast (electronic
ballasts tend to be better, and the "residential grade" ballasts in cheap
fixtures are often what I would call stool specimens.

3. Phosphor formulation of the bulb - which affects color temperature and
color rendering properties. There is a usual trend for less light if the
color temperature is higher than 4100-5000K and/or if the color rendering
index is higher than 86.

- Don Klipstein )