Re: Who has good pricing and experience with PIAA bulbs

["Smith, Kirby A" <kirby.a.smith@lmco.com>]

quk@isham-research.demon.co.uk (Phil Payne) commented re a message by
Hulda Jowett 

>> The bulbs are coated with ion crystal (whatever it is?). It
>>Supposedly does NOT reduce the lights output such as a plain old
>>amber colored filter would.

>There go the laws of physics again ...

Well, if we must invoke the laws of physics, then theoretically one
could coat the glass (or quartz if the lamp is tungsten-halogen)
envelope with a dielectric filter coating that reduced the 4% Freznel
loss in the yellow while adding loss to the red and/or blue spectral
region slightly, thus ending up with a lamp with the same luminosity and
a slightly more yellow cast.  I'd be surprised if PIAA accomplished this
with no net loss, although the process would cost enough to explain the
high price.  Given that the eye's sensitivity is logarithmic, some loss
would not be apparent.

....  Kirby  (kirby.a.smith@lmco.com)
New Hampshire, USA
2 X 1988 90q