A Lamp/lightbulb that emits a type of light that inverts the colour of whatever it shines on!
An example of this can be seen in Microsoft Paint, open up a picture and press Ctrl + i.
If applied in a strobe type device it would really space you out... or cause seizures....-- emjay, Dec 24 2006 Afterimage http://en.wikipedia.org/wiki/AfterimageWho needs a special lamp? [csea, Dec 24 2006] //a type of light// Whereabouts in the electromagnetic spectrum do you intend to find that type?-- pertinax, Dec 24 2006 Well I'm not a physics expert, but I know that a red sock is red because it absorbs green and blue wavelengths from white light and only reflects red. Therefore, perhaps the light needs to react to pigments differently and be absorbed or reflected in the opposite way to usual.
It's probable that this will only be possible with a special paint or something like that...
And besides, I've done my HALF of the idea :P-- emjay, Dec 24 2006 //And besides, I've done my HALF of the idea // But it's the wrong half!-- Ling, Dec 24 2006 Who needs a special lamp? Your eyes will do this for free. See [link].-- csea, Dec 24 2006 The light absorbed by an object is similar to the light it emits when its hot, so here's another way to do it:
Heat the object to white hot and don't give it any illumination. Wear light filters to reduce the intensity as much as sunlight intensity is reduced between looking directly at the sun and looking at something white in sunlight.-- caspian, Dec 27 2006 You might be able to achieve this by actively targeting oppositely-colored laser light onto the objects with enough intensity to overwhelm the object's original color, provided that the object has some reflectivity (e.g, a red plastic ball might actually reflect a little bit of green light, even though it absorbs most of it).
Your bulb would have to have a camera and an active laser targeting system that's fast enough to 'paint' its entire target with the appropriately colored light.-- cowtamer, Feb 12 2007 random, halfbakery