Thing-a-day.com

via mefi, an interesting and simple to make optical illusion.

Instructions: stare at the black dot, don’t look elsewhere. After 20 seconds the image will shift. If you don’t shift your gaze it will appear to be in colour, but as soon as you look somewhere else it goes back to black and white.

The instructions are very straightforward.

1. open the original colour image in photoshop and create a duplicate layer
2. select the bottom layer and do image –> adjustment –> desaturate
3. pick a 50% grey from the colour palette
4. select the top layer and do edit –> fill; use foreground colour, mode = luminosity; opacity = 100%
5. still on the top layer image –> adjustment –> invert
6. make a new layer and draw a black dot in the middle
7. save as jpg
8. delete bottom layer and save as a second jpg
9. either create an animated gif or follow instructions to make a mouseover effect

I did an even more fun standalone page where you can control how long you look at the negative image, then you mouseover to flip to the actual image.