Light decomposing when moving your eyes

[matiasmorant]

last night i was in a bar, and i noticed that when i moved my head fast from left to right and right to left, i could see the reflection of white light in the beer barrels decompose in three colors. why does that happen?

 

[Drakkith]

What were the beer barrels made out of? Glass?

 

[A.T.]

What kind of light source was it? If white light is generated by mixing colored light pulses that have a slight time offset (like CRT color TV), such effects can occur.

 

[sophiecentaur]

Can you repeat the experiment sober?
Could you find the bar?

Sorry - that was a very 'drinkist' reply.

 

[Ibix]

I've seen the effect with a projector that produced images by flashing coloured LEDs in sequence at a mirror array. The flickering was fast enough that you saw mixed colours, but if you moved your head fast you could offset the R, G and B images on your retina slightly. This sounds similar. White LEDs don't work this way, do they?

 

[sophiecentaur]

When the three coloured images flicker and are not produced at the same time (when they are multiplexed sequentially) and you scan in some way - either by moving your eyes or the display - then they will appear in different positions in space.
That could explain it. It would depend upon the particular display. You could experiment by waggling a hand held mirror to stretch the effect more. Girlies often have these in their handbags so you could, perhaps borrow one next time you're there. (Original chat-up line!)

 

[haruspex]

This effect is sometimes used intentionally. What appears to be a narrow strip of steady white light is actually a rapid sequence of consecutive multicoloured strips out of a complete picture. By scanning your eyes across the strip the original picture becomes visible. There's an example at MONA in Tasmania, and another at Mont Orgueil Castle in Jersey.

 

[matiasmorant]

Drakkith: the barrels were made of bright steel
A.T.: there where multiple lights around, there was a projector, light bulbs, light of cars driving by the street... i would say the reflection in the beer barrels wasbeing produced by the light bulbs
Ibix: It does indeed sound similar. But I don't think that the reflection was coming from some electronic device, I think it was just coming from the light bulbs, even though it might well be the case that I got the wrong impression. I believe white leds just produce 'pure' white light...
sophiecentaur: hahahah! that would indeed be an original chat-up line!
haruspex: yes, I understand. but i was wondering if i could decompose the reflection of an actual white light by moving my head very fast?¿

 

[haruspex]

i was wondering if i could decompose the reflection of an actual white light by moving my head very fast?¿

No. There needs to be some time separation of hues in the original light.

 

[JustinRyan]

I would like to repeat this experiment for myself. What were you drinking?

What is "pure white light"?

 

[sophiecentaur]

I would like to repeat this experiment for myself. What were you drinking?

What is "pure white light?"

It's a new cocktail. You haven't tried it?

 

[A.T.]

Drakkith: the barrels were made of bright steel
A.T.: there where multiple lights around, there was a projector, light bulbs, light of cars driving by the street... i would say the reflection in the beer barrels wasbeing produced by the light bulbs

It was the projector. I observed the same thing today. Look at the lens from the side, so it doesn't blind you. Then perform some rapid eye movement. In my case it was this model: