Re: compact flourescent bulbs in enlargers

"Robert Feinman" <[EMAIL PROTECTED]> wrote in
message news:[EMAIL PROTECTED]
> Now that there are a wide variety of screw base
flourescent
> bulbs offered, I'm wondering if they might be useful
instead
> of a 212 or like enlarger bulb.
> It would seem that the high blue and green content would
make
> the exposure times short and there would be little heat.
> I suppose it would be necessary to leave the bulb on and
use
> some sort of shutter to control exposure.
> Anyone ever try this?
>
> -- 
> Robert D Feinman
> [EMAIL PROTECTED]
> Landscapes, Cityscapes, Panoramas and Photoshop Tips
> http://robertdfeinman.com

  Its worth a try but most of these lamps are lower in
intensity than a 212, which is 150watts. I think it might be
closer to a PH211 (75 Watt) lamp. The 211 is the one most
often used in enlargers like the Omega D-2. Condenser
enlargers image the surface of the lamp on the lens. You
might need an auxillary diffuser over the bottom of the lamp
to get uniform illumination. Probably a disc of thin
diffusing plastic would do. Again, it should not be
difficult or expensive to try this out.
  I have given these lamps some thought as a possible source
in a diffusion source for converting an 8x10 camera into an
enlarger. The lamps are self contained and need no starter
or ballast so all one needs is sockets. Since my concept is
one where a lens in a shutter will be used the lamps can be
kept burning throughout a session. Fluorescent lamps like to
run hot. The compact lamps are no exception and take several
minutes to come up to full intensity.
  Another place these lamps may be useful is where the
original enlarger lamp is no longer available as is the case
for large Elwood enlargers. These use a combination of an
eliptical reflector and diffusion glass so the exact shape
of the lamp may not be critical. The original lamps were 300
to 500 watts so it might be difficult to get enough light
from a compact fluorescent.
  The compact lamps I use as houshold lamps have a visual
color similar to incandescent lamps. I suppose you could get
the actual spectral curves from General Electric or other
manufacturer of the lamp. If the spectrum is not too
different it would make the use of variable contrast filters
possible.

-- 
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Richard Knoppow
Los Angeles, CA, USA
[EMAIL PROTECTED]