In <[email protected]
Wow. I haven't had a crappy CFL like that in years. At the time it was
a Philips lamp. All the cheapos from Home Depot are at full brilliance
immediately - at least it's so subtle I don't notice it if they're
not. Those Philips lamps OTOH were very dim at first.
CFLs generally get hot, and need to be formulated to be most efficient
when they have stabilized in temperature.
They are sensitive to temperature, by being dependent on mercury vapor
producing 254 nm UV. Too cold, and there is not enough mercury vapor.
Too hot, and the mercury vapor absorbs 254 nm UV.
Many CFLs have the mercury formulated into an amalgam so as to achieve
optimum concentration of mercury vapor when the CFL has warmed up.
CFLs with outer bulbs have their tubing getting even hotter - so there
is even more need for warmup. On the other hand, those actually do well
over a wider temperature range once they warm up - and include most
advised for outdoor use.
If you want CFLs that start brighter and have less need to warm up, go
for ones with bare tubing rather than outer bulbs, and try for ones with
larger tubing and larger overall size for their wattage. Ones with 15 mm
tubing often start at half or a little over half of full brightness.
Ones with bare tubing warm up faster than ones with outer bulbs. If
the design is for greater compactness and need for more warmup, then at
least that will occur faster.
- Don Klipstein ([email protected]