[Adam Murphy (OP)]

Pavel sent us a message saying:

"Take sunglasses and remove one lens. Watch a normal television film with one eye darkened by a sunglass lens, and the other free. The film will appear in 3-D. Can someone explain to me, how does this work?"

Any insights?

[EvaH]

We've answered the question this week on our show, and you can tune in to hear the answer here...
https://www.thenakedscientists.com/podcasts/question-week

Grab your sunglasses and give it go!

[ProfNewton22]

Hey there,
unless you haven't already received an answer, i've stumpled upon this explanation:
"These glasses utilize special red / cyan lenses to interpret the image. These lenses produce the images you see by color filtering the layered image that you're actually looking at. While one lens filters out all the red in an image, the other lense filters out the cyan, causing your brain to see the picture in 3D"
Hope this may help.
greetings 

[evan_au]

These glasses utilize special red / cyan lenses to interpret the image

This question is not about presenting 3D images using colored lenses.

It is about a 3D effect that occurs when the image presented to one eye is dimmer than the image presented to the other eye, called the Pulfrich effect.
- Listen to the QOTW answer to the podcast.
- As I understand it, effectively, your eye adopts a longer "exposure time" when the image is dimmer, producing a delay in the image from the dimmer eye.
- This means that a moving object appears to be at a different position in the visual field between the "fast" and "slow" eye.
- With binocular vision, a difference in position of an object between the left and right visual fields is interpreted by the brain as being due to parallax, which it interprets as a change in distance to a moving object.
- So the distance to an object moving left-to-right is seen to be different from the distance to an object moving right-to-left.

See: https://en.wikipedia.org/wiki/Pulfrich_effect