For those of you who care to hear some blah-blah about fluorescent lamps.
Compact fluorescent lamps (CFL's) are actually hot cathode, very hot
actually, in a confined space, if that is a concern with cold cathode
heads. Hot cathode lamps have a filament that 'preheats' the gas inside to
allow easier starting thru thermionic emission. Cold cathode fluorescent
lamps (CCFL's) have no filament but are optimized to start by brute force
high voltage field emission. I don't know if they run cooler, but would
assume so because they're used in laptop pc's for display backlighting. At
least they consume less power doe to lack of filament power, but since some
are so tiny, they can have a high concentration of heat for their size and
frequently confined space installation.
Not as hot as halogen lamps, true, but hotter than longer fluorescent tubes.
Color-termperature-wise, they are available over a range of 'average' color
temperatures, but not necessarily stocked by retailers. If I remember, 2700,
3500, 4100 and rarely 5000 K. I don't know if CFL's come in full spectrum As
they age, their color temperature can drift a bit.
They have uneven spectra, very 'peaky' at certain wavelengths, and then
there are some called 'tri-phosphor' types ('Designer' or 'Spec' product
lines GE and ...Philips?...it's been a while, I don't remember) that produce
three distinct spectral peaks that your brain 'fills in' the missing
spectral content, thinking they're full spectrum. True full spectrum
fluorescents are actually pretty 'full'.
Oh yeah, they work by producing UV and the phosphor coating recipe is
'tweaked' to respond to the UV. The phosphor converts the UV to visible
light, but some significant UV content is still present.
But since cold cathode enlarger heads exist, I'm not going to second guess
anyone from the comfort of my armchair about how well they work or if they
need filters, because I don't know anything about that part.
I used to design electronic fluorescent ballasts.
'nuff said on that.
Murray
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