Julius von Bismarck's 'Image Fulgurator' projects images into the photographs of strangers, while those stragers remain oblivious to the trickery behind this extraodinary gadget.
Julius demonstrates the use of his gadget on his website by showing photos that had unexpected projections visible only when viewed after the fact. One surprised observer at the Berlin wall proof-of-concept demo could not believe her eyes when a phantom image showed up on her boyfriend's photo of the "YOU ARE ENTERING THE AMERICAN SECTOR" sign.
How does he do it? The concept is very simple: The Image Fulgurator (which looks like a retrofitted camera-gone-rogue) detects the firing of a nearby flash and then projects some random message onto the subject being focused on at the moment the picture is snapped. Almost invisible to the naked eye, this ghostly image comes to the fore on the photo that eventually emerges on any standard digital or film camera.
Here is a demonstration of his gadget in action:
To retain the element of surprise - he has cleverly devised a way to focus the projection in a preview window within the Fulgurator's body!
Readers of an article posted on one of the websites discussing this creation came up with a few ideas how this could be used: an anti-paparazi device which follows a celebrity and renders paparazi's photos useless by interfering each time their flash goes off (at night or using a flash fill during the day). Interested learning more? Check out his schematics and patent description here or visit the artist's website.