You can even set it as your desktop wallpaper, and most animated .gif files will actually cycle continuously. Pretty cool stuff.

Here is another eye fatigue / persistence of vision optical illusion you all may enjoy.

Focus on the tip of the nose, the chin, or the pendant around the neck. The picture will alternate every 10 secs.

Michael

http://tinyurl.com/2fo2s5

I prefered the pendant

:)

The tank top works even better. I just tried it.

Fantastic

Indeed: that one is rather good!

I don't think the mechanism at work in the pool table illusion is "chromatic adaptation". I think this works by means of an afterimage (of the coloured balls) being superinposed on top of the image of the black and white balls. You can demonstrate the fact that you have formed a coloured afterimage by looking at a white surface after staring at the coloured image for a while (about the duration set in the film). You should then also see the coloured pool balls.

You are right david; It works by a combination of Retinal Fatigue and Persistence of Vision.

For those interested in making one of these images, use your favorite editing software (Photoshop, Elements, Graphic Converter, etc.) and follow the steps below. These were used to create the young lady illusion linked-to above.

1. Layer two identical images.
2. "Greyscale" one image (i.e. make it B&W), and "Invert" the other (i.e. make it a photographic negative).
3. Produce an Animated Gif with a 10 sec. loop.

Michael

For some other less striking, but nonetheless cool examples, go to this page about Chromatic Adaptation.

As far as I was aware, Persistence of Vision is what is at play when viewing film or animation. Because the images are not rapidly changing in this illusion (the pool table...not the spider), I don't see POV's role in the optical puzzle.

This talk of explaining the illusion through retinal fatigue sounds strangely familiar...

Andini,

Since the retina is "retaining an image" from one point in time to another, it can be seen as a form of Persistence of Vision. Regarding the phenomenon as used in frame motion; there has been for some time a debate whether this is even an accurate notion. There in a nice article found here; http://www.uca.edu/org/ccsmi/ccsmi/class......ited.htm

And yes, you did mention the Retina Fatigue above. My brief explanation came from another more in-depth thread made about a year ago on another board (by a variety of authors) where I dissected John Sadowski's Castle Illusion. Mine was not derivative of your post; apologies if it seemed that way.

Michael

Here was my original post made last June on another board. I thought it may prove interesting to the folks reading this thread. Be sure to take a look at the wonderful Spanish Castle Illusion (linked to by Andini above) before going further. This was posted after a thorough explanation of the illusion of provided, and used only to illustrate those points.


---------------------------


Below are the four images (2 real, 2 virtual) that you experience while viewing this illusion.

1) The Real Black and White





2) The Real Negative Color Image





3) The Virtual Inverted Negative (i.e. Positive) Color after-image that appears on your eye due to "retina fatigue". (To create this image, I color-inverted #2)





4) The Virtual combination of #3 and the #1 that appears by superimposing the after-image on your retina with the actual B&W. (To create this image, I gave #3 a 35% transparency, and laid it on top of #1)

Thanks for the links!
That was pretty amazing ^^

Very awesome, great stuff.

Thanks.

Also suggests that latent / negative image formation is part of how we detect edges in our visual perception.

Amazing pool table and castle illusion! Thanks for those. And the tank-top.