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RE: [TCML] Ultra-high speed movie of lightning arc channel formation
These are made from balancing photo paper, photo film, or X-Ray film (in this case 8"x10") on top of a Tesla Coil in a completely dark room. For obvious reasons, the spark gap also has to be hidden in something light-proof. The sparks, which issue from a wire, ball, point, or any other form the topload of the Tesla Coil expose the film instantly and leave an accurate record of the arcs, sparks, effluves, corona, and whatever else. Of course, you can only do this with small amounts of current or else you'll ignite the materials on fire!
I should mention that the photos on my site which are white paper or bluish film and black sparks are "negatives". These in turn are inverted to make the real image, white sparks on black backgrounds. For photo paper, I simply inverted them in Photoshop. For photo film, I placed the film on a piece of photopaper and exposed it like any other negative. [I should also mention I know nothing of photography, and any pictures on my site that turned out okay are purely chance. Many of the paper and film exposures I did are yellowed now from using the wrong chemical or ratio, etc...not knowing what I was doing]. [Nearly every photo on the site was taken with a digital camera, except those from the mid 90s which were taken from an old Polaroid and scanned - I have two Olympus digital cameras that can take up to a 1 second exposure, the latest is a Cybershot 7.2 megapixel, the former a 3.2 megapixel]
Immediately afterward, the blank (but exposed) photographic paper or film is developed, thrown in a stop bath, and "fixed", then hung to dry on a clothesline - standard photography.
Its a messy process. To keep everything flat, I normally fix the paper to a piece of glass and balance that (paper down) onto the coil.
In the case of Pancakes, and low frequency Tesla Coils, you can get a lot of neat static electric effects (odd branch formations, phantom streamers, etc.) that you can see develop in the air, but to take a regular photograph (even using advanced photographic techniques) there is never enough light from these discharges to develop properly - and they never show up. [There may be some night-vision camera or something out there that can show them, but conventional photography simply doesn't do it. I've tried for years. Its a shame - and frustrating - because you can see these things clearly with the naked eye. But most of the time they are moving (and faint), making the need for a long exposure, which only ends up in a faint blur at best. What is needed to capture these little formations is an instant exposure - but again, there is not enough light given off to allow this. Even 30 second exposures are almost useless. You can see a nice blurry corona that shows the roots of these phenomena (where they are the brightest), but the actual shape and forms are completely obscured.
This process was exactly how Lichtenberg figures were made originally on dust plates. Lord Armstrong and others experimented with these, and you can too - take a dusty piece of glass and put it on your coil - switch it on a moment and you'll see a nice pattern of sparks. But this effect with dust is a bit like reverse powder coating something using a Tesla Coil. You are really scattering the dust. With photographic emulsion, the light from the sparks actually develops the paper/film, as "sparks". The sparks occur pretty much at the surface plane of the paper, which limits the exposure to something a little too "2D". What you see in those photos is pretty much what you see with your eyes when you look straight down on the paper while its happening, disregarding the effects that aim upward away from the paper. [Kinraide did some neat things, like place the plates in different planes, but balancing glass plates is a lot easier than photographic paper, espescially in a dark room!]
A lot of these strange sparking effects require tweaking of the circuit in such a way that they occur. (like the arrays of sparks from VTTCs and solid-state coils - much different than conventional coils)
Tesla described them matter-of-factly in the lectures, but there is nothing easy about their creation. A normal Tesla Coil and this technique will produce an exposure almost black and looking like spaghetti from all of the overlapping sparks. You need a coil that produces as few as sparks possible as long as possible and with all of the branches and associated phenomena you're looking for.
This can be by varying the current of the high voltage transformer in small increments, changing the capacitor size in small amounts, and varying the spark gap, even by thousanths of an inch), and keeping your fingers crossed the whole time.
The coils used were either relating to Kinraide experiments or old X-Ray Tesla coils. I never used cylindrical coils for these photos, because I could never get the same effects as well-produced as with the Pancakes. Its not impossible, but the only times I have been able were with large cylindrical coils and tiny amounts of power, which seemed impractical when I could use a flat coil 9" in diameter and 2" tall and get better results. Also, for the most part, the nicest "branching" effects were made with tank circuits using high voltage transformers of only 1 or 2kV. With higher voltages, the sparks from the Tesla Coils tended to all look alike. As mentioned before, small changes in the circuit creates great effects when such low voltages are used. The low voltages seem to produce the most curious effects.
> From: Gary.Lau@xxxxxx> To: tesla@xxxxxxxxxx> Date: Tue, 12 Aug 2008 00:27:40 +0000> Subject: RE: [TCML] Ultra-high speed movie of lightning arc channel formation> CC: > > Hi Jeff,> > Those are beautiful images, more from the realm of sci-fi movies than from any TC photography I've previously seen. I'm not sure it constitutes high speed, but awesome to look at none the less!> > But I don't have a good sense of just what it is I'm looking at. I understand that you use a very low-value mains fuse to limit the on-time of the coil, but I don't understand the relationship of the film (positive photo paper?) and anything else. What is it that's in contact with the paper? Are we looking at surface tracking across the paper, or something else? What is the scale? What are the coil specs? Did you develop the film?> > Regards, Gary Lau> MA, USA> > > -----Original Message-----> > From: tesla-bounces@xxxxxxxxxx [mailto:tesla-bounces@xxxxxxxxxx] On> > Behalf Of Jeff Behary> > Sent: Monday, August 11, 2008 7:08 PM> > To: Tesla Coil Mailing List; jeff_behary@xxxxxxxxxxx> > Subject: RE: [TCML] Ultra-high speed movie of lightning arc channel formation> >> >> > Bert,> >> > This is not so high-speed, but I did a few tests before as Lichtenberg Figures> > directly on photographic film or paper. For the coils, I used small glass fuses, the> > fastest-blowing at the smallest amperage I could find (at the local hardware store).> > The concept was pretty simple, simply turn on the coil and the fuse was instantly> > blown in a fraction of a second. (what fraction, unfortunately, I don't know). What> > is interesting, is the amount of sparks generated (and the branches, effluves,> > brush) in such a short amount of time. Granted, a 1/100th or 1/20th of a second> > may be considered a long time for this sort of exposure, compared to high speed> > cameras, but maybe not everything can be captured quite as easy with a camera> > as by direct contact. If only there was high-speed exposures possible directly on> > film. (Sounds like a new invention!)> >> > http://www.electrotherapymuseum.com/2005/2005-06-> > 23/images/CencoDC0001ic.jpg> > http://www.electrotherapymuseum.com/2006/KinDis1/images/ED0009a.jpg> > http://www.electrotherapymuseum.com/2005/2005-06-> > 23/images/CencoDC0000ic.jpg> > http://www.electrotherapymuseum.com/2005/2005-06-> > 23/images/CencoDC0002ic.jpg> > http://www.electrotherapymuseum.com/2005/Film22May/images/FischerCenco000> > 1.jpg> > http://www.electrotherapymuseum.com/2005/Film22May/images/FischerCenco000> > 8.jpg> > http://www.electrotherapymuseum.com/2005/2005-06-14/images/Glossy20002i.jpg> > http://www.electrotherapymuseum.com/2005/2005-06-14/images/Glossy20001i.jpg> > http://www.electrotherapymuseum.com/2006/KinDis1/images/ED0005b.jpg> > http://www.electrotherapymuseum.com/2006/KinDis1/images/ED0007a.jpg> >> > I can try to recreate some of these at a later date with a more precise way of> > measuring time, maybe an X-Ray timer or something similar. I'm sure there is> > something this half of the century that is more accurate than whats in my junk pile.> >> > It would be interesting if a roll of photographic paper/film, large format, was rapidly> > moving, like being transfered from a full roll to an empty roll spinning in a lathe, with> > the coil discharging in one spot (say, centered on the roll's width). If the> > mechanical constraints worked out so that the paper/film travelled smoothly, even> > at high speed, it would be an interesting experiment to see Lichtenberg figures at> > so many feet per second, how many, and how they change. Damn hard to develop> > and fix such a long photo, but still, it would be fun.> >> > I've seen the slow branching effect before with Tesla Coils. A coil that can give a> > spark, say 3 - 4 foot long, operated at a fraction of the power normally used (less> > than 100 watts, for example) with the spark gap open just enough for it to fire once> > or twice a second (but not cease to fire). The sparks become very branching,> > static-like, and strangely seem to low down just enough for you to make out the> > invididual branches. Unfortunately you need your nose pretty close to the sparks to> > really study this, and I've had a few too close for comfort. Despite the low current,> > these sparks are beautiful but not very friendly to get tangled with.> >> > Jeff> > _______________________________________________> Tesla mailing list> Tesla@xxxxxxxxxxxxxx> http://www.pupman.com/mailman/listinfo/tesla
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