EEVBlog #1131 - £1M Prank - Banksy Artwork Shredded! HOW?

A look at how the Banksy artwork prank "Girl with a Balloon" shredded itself moments after being sold for £1M at a Sotheby's auction.
How long did it sit idle waiting to be triggered?, and was this actually possible?
NOTE: The Artwork was authenticated by "Pest Control", which is Banksy's own authentication house. If the artwork was delivered to them for checking before the auction, this is when they installed the mechanism. I still think the at least the seller has to be in on it, and likely the buyer (otherwise they could sue Banksy and bring his real name into the public). And if Sotheby's were in on it (they'd lose their reputation if they were) they look like fools. Lose--lose for Sotheby's.

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[EEVblog]

NOTE: The Artwork was authenticated by "Pest Control", which is Banksy's own authentication house. If the artwork was delivered to them for checking before the auction, this is when they installed the mechanism. I still think at least the seller has to be in on it, and likely the "buyer" (otherwise they could sue Banksy and bring his real name into the public). And if Sotheby's were in on it (they'd lose their reputation if they were) they look like fools. Lose--lose for Sotheby's.

[stevec]

I think the bidder overpaid since it's only $8.99 on allposters.com.

[mikeselectricstuff]

10year standby for the receiver would be very simple-motion sensor to put it to deep sleep if not moved for a while. Then a 2-stage "arming" wakeup by a long transmission to a receiver waking at a period of few tens of secs, and a trigger once it woke up.

[TheDefpom]

As soon as I saw the exacto knife blades I knew it was faked, as you said, no way they would cut it placed like that, even if the canvas could have run past them.

[MoritzvonSchweinitz]

For more on Bansky's very interesting relation to 'art' and the art market, I can highly recommend the documentary 'Exit through the Gift Shop' - but only if you watch it til the end. It has some twists in it!

[voltvids]

I haven't read any comments so I don't know if anyone else has thought of this but this is the simplest circuit in the world. Everyone focuses on the batteries and how they could never last 12 years as the remote control circuit would drain the cells in standby. This is correct, but only if the circuit is powered up. If it is totally disconnected there is no load. How? A closed loop timer circuit is how. A simple 555 timer circuit with a relay to completely disconnect power from the entire circuit after a specified time. This timer circuit triggered with the simplest of devices, a vibration switch. Paintings are something that normally never move so the entire circuit is sitting there waiting for the day that it gets moved to say the auction block. Any type of remote trigger could be used at this point. Radio, infrared, even a cell phone. Power consumption would not be an issue if the receiver was only powered up for say an hour every time the painting was moved. This way battery life would not be an issue. Lithium cells can last 30 years under no load.

[PaulSteMarie]

No way in hell Southby's security would have missed that. They were absolutely aware of it.

You're talking about a place that handles treasures on the order of the British Crown Jewels every week. I daresay nothing comes in or out without being x-rayed, ultrasounded, etc.

[bborkzilla]

The "Art World" thinks it's actually worth more shredded than before, because of its uniqueness. What a crock.

[zyzzy]

Great video, thanks. However, I think it was pre-shredded. Stop your video at 2:03 and look at the girl in the un-shredded and shredded parts. To me they don't line up lengthwise. In other words, the girls feet are coming out the bottom before they should be.

Jack

[marko_z_bogdanca]

There also is a possibility that the picture was not destroyed. I can easily imagine that the original is still there inside of the frame rolled safely on a separate roll. This was a show :)

[colbatguano]

Nah, you were right with the magicians roller blind trick. The original art gets rolled up and the pre-shredded art gets spit out. And yes, Sotheby's was in on it. Consider that the purported owner goes to Sotheby's and says I have a Banksy to sell. Very good, but Sotheby needs to verify it it legit. There are no museum art dealer or auction house stamps on the back so Sotheby's needs to due diligence which means taking the art from the frame. Particularly if the frame weighs what - over 20 pounds? - at the very least to verify it's not a bomb. The actual art still exists in the frame because someone paid £1M for it - if the art is damaged then Sotheby's is on the hook for 'restoration costs' or diminished value, etc damages. The actual mechanics of the shredder seem suspect - I doubt a battery driven mechanism would evenly pull a painted canvas through even a commercial shredding engine (someone can do the math but I suspect even a wall mains powered shredder would have a tough time). The easiest solution is usually the right solution - most elegant and most likely to actually work. One small motor unrolls and another rolls up. Most of the mechanical nonsense in the Banksey supplied vid isn't even in the actual frame. The buyer has the original artwork to enjoy and a shredded copy also from the artist. Now, if you think that speculative high-end art is legit, consider that this work sold for 3 times it's pre-auction estimate. Is it likely that the buyer was in on the scam? Heavens...what has the world come to? Is Banksy part of the money grab? You be the judge.

[hinoarts]

As the Sotheby's listing says it was "Authenticated by Pest Control" which is Banksy's "handling service".
I assume part of their job is to "inspect" the works before they go to auction and this is how they did it. Probably the switch for the receiver was activated just a few days before the auction.
But for the shredder another theory is that it could have been a wind-up mechanism which wouldn't need batteries. Is that possible?

[Azeazezar]

Isn't the battery drain avoidable by turning it off untill it detects significant movement. And then return to an off state after a week or so.

[Laz_Arus]

Here's a thought. There was the original and a pre-sliced copy hidden directly underneath.

At hammer time, two motors wind the top original onto a takeup roll at the bottom of the frame, like an old film camera, and the fake pre-sliced copy is fed out of an adjacent slot at the bottom.

Nobody would be able to tell from a distant that the shred was a copy. That might also explain why Sotherby's whisked it away before anyone could have a closer look.

All together though, a might fine prank.

I wonder if Sotherby's still get their 10% (or whatever) commission ?? Expensive prank if they do .. lol

[MrSnoots]

The shredded canvas comes out too smoothly. Even a good commercial strip shredder is going to cause vibration and noise. Plus, this is canvas, not paper. The chances of it getting jammed make it impractical.

My vote is preshredded copy being fed from the back as the original is rolled up.

[Basement-Science]

So what do we learn form this? You can smuggle a bomb anywhere if you just hide it in a priceless piece of art ;)

[ddragon]

I must admit I laughed my tits off when this came up in the news! xD
Apparently another "owner" of a Banksy has since taken a knife to his one intending to double it's value...Only to reduce it to about £1! :-p

Anyhow, some thoughts on the prank:...
1. The shredder hardware's definitely the regular strip-cut type, and the canvas tail was sat in the blades for ages beforehand. (Note how the canvas is "set" like it is.)
2. The auction was probably live-streamed, and the shredder could've been operated via SMS message from anywhere. An Arduino with a GSM shield and a contract SIM is all it would've taken. (Note how quickly after Banksy tweeted his "Going, Going, Gone". He had both a video feed and internet access at the time. Could've been in the audience too ofc.)
3. Batteries is puzzling me...But assuming this was a long thought out prank and the seller was in on the game, he could've arranged to pop some batteries (And maybe a pay-as-ye-go SIM) just prior to packaging up for auction.

[therealjammit]

Here's my idea.
1) You install a battery that has an amazing shelf life, most likely primary lithium cells.
2) You then make an RF resonant circuit that can power a small latching relay coil. Think crystal AM radio.
3) At the correct time (perhaps when they have an item viewing a week before the auction) you use an RF transmitter to power the latching relay. A 1 watt (2 watt PEP) should do nicely, especially at a few feet and you can hold the transmit button down for a little while to accumulate a charge for the latching relay. Either the audible "click" or perhaps a transmitted "I'm on" signal would work.
4) The latching relay connects the long shelf life batteries to the real receiver circuit for later triggering.
5) With the circuit powered up and waiting for an input signal, a plant in the audience would send a remote signal to the now powered up receiver to start shredding.
6) You will probably need a few plants. A couple of people during the earlier viewing, each with a transmitter, to make sure the shredder circuit is powered up and a few people during the auction to make sure the shredder gets a proper "shred now" signal.

The silver oxide batteries have an incredible shelf life when the seal hasn't been punctured, but I've never seen a "D" cell version. The shelf life of an alkaline is about 5 years, and primary lithium cells do have a shelf life of about 10 years. If you can remove the "phantom" power losses (ultra-low standby micro still uses some power) you can reach the shelf life of the battery, which is why my idea uses the RF powered latching relay.

[TheGFS]

The orginal owner was probably Banksy him self, just putting on a show :)

[nachiswichis]

At 1:59 I think the auctioneer presses a button under the desk