Maybe you’re curious about light graffiti, but how does it actually work?
The short answer is that when you open up the shutter of your camera and draw an image with a light source, the camera records all light in front of it as if it happened at once. It’s recording the light without regard to what time the light comes in, just like a piece of paper records a pencil’s lead, but not at what time it was scribed there.
An illustration of How Light Graffiti Works:
This animated GIF should show things somewhat more visually (as I attempted to do with this glowing display). My camera was set to take several shots one after another at a pre-determined exposure time. In this animated GIF each frame is actually the product of it and every previous frame added together with GIMP (how the double-exposures were made and the animation). The end product is equivalent to what happens in a camera when the shutter is opened and it captures all of the light going in.
To put it another way, Read more »