Channels. There are a number of ways we can trick our eyes and brains to see differently. These visual effects are easy to create, but you must find a pair of the special glasses that 'unlock' the third dimension.

original image to be manipulated This process will work with any color image opened in Photoshop in RGB Mode. RGB refers to the Red, Green, Blue channels found in such an image.
Red channel is chosen
Choose the Red Channel on the Channels palette (Command -1), Select All (Command - A). The red channel visible seems black & whiteIn Photoshop. you can hold the Command key down while tapping the left arrow key 5 times in succession to shift that channel to the left. Make all channels visible again by choosing the RGB (Command - ~)
3-D image with red-green shift ...and step back. Your red filtered eye (right) sees one image and your left eye is seeing the other image through the green filtered side. When the two images superimpose themselves in your brain the illusion of 3-D is complete.3D glasses