On 26 Feb 2007 03:36:31 -0800 someone who may be "gmw"
wrote this:-

I have just used a photographic exposure meter to compare the light
output of a CFL bulb with various pearl light bulbs.

A camera light meter. Not quite the right thing to measure the
output of light bulbs, though it will give some indication.

What sort of CFL were you measuring with the camera meter? Some
designs take a while to achieve full brightness.

The CFL is a 20W bulb claimed to be equivalent to a 100W bulb. It has
had about 1 year of evening use.
Its measured light output is a little LESS than a 60W 2000h pearl bulb
rated at 555 lumerns, and ~40% of a 100W 2000hr bulb.

I note with interest the different conditions. From what you have
typed it appears that you compared the output of a one year old CFL,
measured with your meter, to the claimed output of two bulbs, the
age of which you don't state. Fascinating.

Having replaced several 100W pearl light bulbs with "100W" CFLs

Where were these installed?

we have reverted to pearl in all but one room.

For what reason(s)?

These misleading claims must be understood and ruled out.

Though earlier you typed that these claims were presumably accurate.
Why should accurate claims be ruled out?

CFLs are not yet ready to replace conventional bulbs.

Incorrect. In most cases there is now a suitable energy saving bulb.
The number of cases where such bulbs are not suitable has been and
is being reduced.

At one time such bulbs were really only suitable for relatively
large fittings with lamps that were left on for long periods. This
was because of the size/weight of the bulbs, the length of time they
took to reach full output and a relative lack of robustness of the
starting mechanism. However, that was in the early 1980s. The
engineering of energy saving bulbs has progressed a long way since
then.


--
David Hansen, Edinburgh
I will *always* explain revoked encryption keys, unless RIP prevents me
http://www.opsi.gov.uk/acts/acts2000/00023--e.htm#54