This is a pretty cool technique that definitely needs to come with a health and safety warning. So, don’t try this at home unless you understand how electricity works and how to experiment with it safely. If that’s you, then you’ll love this video from Hyperspace Pirate. Even if it’s not you, watch it anyway because it results in some pretty cool photography!
It’s a process called Kirlian Photography and it’s used to be able to photograph the phenomenon of electrical coronal discharge. It was accidentally discovered by Semyon Kirlian, after whom it was named, in 1939. It’s a similar principle as those “Plasma Globes” that were so popular in the 80s.
As per Hyperspace Pirate’s description of the process:
The technique uses two clear glass plates with salt water between them. The salt water is connected to a high voltage, high frequency AC source. An AC flyback transformer works for this, but i got better results using a solid state tesla coil operating off a slayer exciter circuit – the same circuit i demonstrated in my previous video. This generates around 40,000 volts at 350 kHz with a 12V input.
The high voltage AC doesn’t conduct through the glass, but causes high voltage charges to appear on the outside surface of the glass plates through capacitave coupling. Because glass is an electrical insulator, the charges can’t move freely along the surface, so when an electrode connected to ground comes near the glass, the resulting discharge “fans” out, as charges from a relatively large area will jump to a single point electrode.
When a flat conductive object is pressed against the glass, the edges and small bumps on its surface will exhibit this type of discharge and glow purple. Since the glass plates and the saltwater are transparent, the resulting glow can easily be photographed.
While any insulating material can be used for this process, he advises against using clear acrylic for reasons that will become obvious once you watch the video. Essentially, the high voltage discharge generates enough heat that it causes it to melt on its surface. Using actual glass, however, no such issue. The conductive objects can be pretty much anything you want, although as the glass is flat, it naturally works best with flat objects like coins, let’s, etc.
Again, you’re dealing with extremely high AC voltages here and potentially a lot of current if you’re not careful. So, if you’re not confident setting something like this up yourself, just enjoy the pretty scenes in the video!