Can I make a video with only magnets?

September 12, 2005 6:16 PM

I want to "break" a video.

Help explain to a non-science-type (read: artist) how video works. I've done some research, but I'm not too experienced with the world of electromagnets and such. Can I use a big magnet (rare earth -- those are strong, right? electromagnets?) and wave it around a video tape to make something happen? I'm not quite expecting this, but would it be similar? I also have a broken camera I can pillage for parts, if that helps. I'm just looking for some more informed ideas, or if someone has experience (or better google-fu than I) before I accidently break my (roomate's) VCR or (school's) video cameras. Analog or MiniDV tapes, whatever. I'm thinking of trying regular VHS first, because the tapes are cheaper.

posted by ruby.aftermath to Technology (18 answers total)

There are tape degaussers designed to erase videotapes (and other magnetic tapes.)

In general, yes, a strong enough magnetic field will erase a tape. If you do it thoroughly, you'd get nothing but static from it. I don't know whether you'd get interesting results from partial erasing (but it's good that you don't expect results similar to the effects of appyling magnets to a CRT, 'cause you won't get those.)
posted by Zed_Lopez at 6:25 PM on September 12, 2005

You will likely erase not just the content of the image, but the syncing information as well. This could make it unplayable completely - i.e. you'll just get the static from the TV. If you want to get weird effects, try heating and stretching the tape. Just remember that a bad tape is likely to get eaten by whatever machine is playing it, so playback in something you don't mind screwing up.

The other thing you can do is try recording something onto a VHS tape, while at the same time messing with the speed of the tape. You'd have to have the VCR open and muck about with the belts that power the tape. You could also try moving the tape up and down across the record heads with your finger. Not sure what that would do.
posted by qwip at 7:27 PM on September 12, 2005

Are you trying to erase it or create a cool effect?
posted by knave at 7:42 PM on September 12, 2005

The title of the post is "can I make a video with only magnets". The answer to that is basicaly 'no'.
posted by delmoi at 7:44 PM on September 12, 2005

Yeah, video is "made" by little tiny magnetic heads directly on the tape, in a very precise coordination of activity. Waving a big magnet around the tape pretty much blows that all to hell.
posted by MrZero at 7:53 PM on September 12, 2005

It is not a magnet approuch and it is not really cheap but you can pick up a circuit bent PXL 2000 video camera on ebay for around $300. If you should happen to find one of these cameras at a goodwill or garage sale you could pay less and have the same guy mod it for you.
It is a lofi kids camera that you can shoot your own videos and edit with 2 vcrs.
posted by sailormouth at 7:58 PM on September 12, 2005

qwip's suggestion will get more interesting effects than applying magnets to the tape. And you'll get better results with VHS than with digital.

One other possibility is to use an unshielded cable to run the signal from one VCR to the other. Then you can apply your magnets to the cable, and you'll get some noise or distorsion on the signal.
posted by RobotHero at 8:01 PM on September 12, 2005

I suppose you could play something out to a screen and play with magnets around the side of the screen to distort the picture while pointing a video camera at the front.

Not really the effect you're looking for though, and you'll end up with one dud monitor.

Something more interesting: video feedback.

Does anyone know what would happen if you passed a video signal through various bits of electronics not designed to handle it? Eg guitar pedals, echo chambers, etc.
posted by Leon at 8:21 PM on September 12, 2005

Oops. Hadn't read your "this" link. Sorry. The video feedback's still cool and abstract, though.
posted by Leon at 8:24 PM on September 12, 2005

Response by poster: You guys are so smart :)

RobotHero's cable idea is something I might try. Basically, I was thinking that film captures light, video is based on magnets. I'm interested in making some kind of image/sound without using a camera, basically for the hell of it. Thanks for the ideas so far, and I guess thanks for setting me straight that magnets on a tape will just mess it up completely, which is what I pretty much expected but am still kind of disappointed about. Because that would have been fun.
posted by ruby.aftermath at 9:10 PM on September 12, 2005

Response by poster: And Leon, video feedback is definitely something I'll try. It, and your question, reminds me of this noise artist I saw a while ago here in Chicago (Satan2000, and unfortunately I can't find a link) who hooks up a whole bunch of effects pedals to each other and just lets them do their thing, with no input. When I saw him the end result was pretty amazing, but he said that sometimes nothing much at all happens. That was kind of an inspiration for this magnet project-that-might-not-be, too.
posted by ruby.aftermath at 9:26 PM on September 12, 2005

An audio signal is a whole lot simpler than a video signal. Without a more complex set up, you'll probably have the choice between static or a strobe. Maybe if you're really lucky, you'll get horizontal lines. So keep your expectations low, is what I'm saying.
posted by RobotHero at 11:22 PM on September 12, 2005

I don't think you can do much with the tape, but....

Find yourself a cheap analog TV and VCR, one with a lot of adjustment dials. Then you can go to town with the sync, color balance, and brightness.
posted by KirkJobSluder at 5:20 AM on September 13, 2005

You can pull the tape out, staple it to a piece of cardboard, and reprogram it with a magnetic card strip writer. They work on the same principle, essentially.
posted by sonofsamiam at 7:13 AM on September 13, 2005

ruby*, here's an idea along the lines of what I think you want to accomplish. You could start with a simple hardware store magnet. Construct a way to manually wind a VCR tape from one side to the other. Some sort of hand crank might work best. The cassette locks the tape from moving, so you will have to press the release button and tape it open to free the tape. That button is on the underside near the label. You will also have to depress the little square button on the side to allow the front door to open.

Take a pre-recorded tape and slowly crank it by the open door. While doing this, gently wave the magnet near the tape, experimenting with distance from tape, frequency of waving, etc. The effect of the magnet will be to degrade the signal that is recorded there. If the signal is somewhat degraded, you might get some interesting effects. If it is significantly degraded, it will not play at all (boring).

The window you are looking to stay within is as follows. Among other things on a recorded tape, there are 2 things of importance to you. A "sync" pulse tells the TV to start the spot on the screen to begin its sweep to the other side. Without that pulse, the spot does not move and you get snow or black. The second signal is a complex one that carries the information that must be displayed as the spot sweeps across the screen. It is the sum of all the information in all the sweeps that creates the picture.

If you degrade the information, it will probably produce some interesting effects. However the degradation must not be so severe as to remove the sync pulses completely. If your magnet waving is just strong enough to degrade the information signal without removing the sync pulses, then by playing with the speed of cranking and the speed of waving, you might produce some interesting patterns.

Good luck. Sounds like it could be fun.
posted by RMALCOLM at 8:27 AM on September 13, 2005

I wonder what would happen if you held a magnet to the side of a camcorder while taping... Try an' lemme know, will ya?
posted by klangklangston at 11:40 AM on September 13, 2005

One thing that is neat to do is to duplicate tapes over and over again. They'll lose contrast, the midgrades will disappear and the sound will get a weird "WAAH-WAAAH-WAAH" thing behind it. My brother bought me a couple of Tarzan tapes from the Dollar Store that had been degraded through lossy transfers, and they're marvellously surreal to watch.
posted by klangklangston at 11:45 AM on September 13, 2005

klangklangston: You would probably seriously hurt the camcorder.
posted by RMALCOLM at 7:38 PM on September 13, 2005