On 5 Dec 2009 21:49:37 GMT, "DoN. Nichols" wrote:

On 2009-12-05, Gunner Asch wrote:
On 5 Dec 2009 01:55:15 GMT, "DoN. Nichols" wrote:

On 2009-12-04, Gunner Asch wrote:
On 4 Dec 2009 03:30:55 GMT, "DoN. Nichols" wrote:

Do you remember the old photographic flash bulbs? They may not
reach the same peak brightness as an electronic flash, but they burn a
lot longer, so the effect on your night vision is a lot greater (along
with the blue blobs floating where the bulb was in your field of vue
when it went off. :-)

And when gently cracked and then placed in or above above a container of
a flammable substance..make very nice and very positive ignitors.

Hmm ... *that* I didn't know.

Might come in handy in the near future...shrug.

Indeed -- given a supply of old unused flashbulbs. (Though I've
recently discovered that they are still made for a niche market -- caver
photographers who need a *lot* of light for their photos.

But did you know that if you placed one or more flashbulbs in
contact with the one which you are about to fire, those will go off at
the same time (or at least close enough so you could not tell the
difference without a scope and a photovoltaic sensor. :-)

Really? What sets the sympathics off? Its mearly a magnesium ally isnt
it?

Magnesium or sometimes very fine aluminum foil or wire -- but in
a pure oxygen atmosphere. So the intense illumination gets the wires
hot enough to start to burn in that pure oxygen atmosphere.

I suspect that a laser could set them off remotely, too.

I'm not sure whether the ones which appeared to be two stiff
wires with one very fine wire coupling them, and everything dipped in a
silver-colored goop and allowed to dry. I *think* that these may have
been the FP lamps -- fast illumination increase to a certain point, then
a wide plateau, and then a decrease back to dark. These were used with
focal plane shutters, which at higher shutter speeds don't expose the
entire frame at once, and electronic flash shows an incomplete image,
while normal bulbs will show a rise of brightness followed by a fall-off
as the shutter traverses the film -- horizontally in most cameras with
focal-plane shutters, vertically in a few.

Since the goop is connected thermally to the stiff wire, the
spread of burning will be slower than it is with the bulb full of fine
wire in oxygen.

Enjoy,
DoN.

Ah! Indeed!

And yes..the long wires are for focal plane shutters. I still have some
samples of those from back in the day.

I think Ive still got a case of Edison base bulbs. I had 2 cases at one
time..but the ability to screw them into standard light bulb bases in
all manner of light fixtures was tough to deal with when I was younger
G

Gunner


"First Law of Leftist Debate
The more you present a leftist with factual evidence
that is counter to his preconceived world view and the
more difficult it becomes for him to refute it without
losing face the chance of him calling you a racist, bigot,
homophobe approaches infinity.

This is despite the thread you are in having not mentioned
race or sexual preference in any way that is relevant to
the subject." Grey Ghost