We can make 3D pictures
(…of varying quality).
On a road trip a few weeks ago, one of the AirBNBs we stopped at left this charming book out as part of their cozy cottage decor: Fractal 3D Magic by Clifford Pickover (complete with included glasses). I was immediately smitten, then obsessed. By the end of the vacation, I was blind-shooting photo pairs for stereograms with no idea if anything would turn out. But I should slow down.
The book. Not entirely sure Clifford A. Pickover is a real name. He has many nerd books available online but be warned one publication is not like the others.
An example of the book’s contents. If you have a set of red/blue glasses give it a shot.
Most people are familiar with the 3D pictures and movies that require those color filter glasses. That is the classic method, dating back to 1891. Some may remember the RealD 3D movies that used grey glasses** - but still required the viewer to wear glasses. 3D in pictures, movies and television pops up every now and again and vanishes seemingly as swiftly and is remembered as gimmicky. So it occurs to me that a technology so stalled and corny should be pretty easy for a DIY project now that we live in the future.
Let’s start at the beginning. How do we perceive 3D? We have two eyes, separated by a short distance. We measure this length as the center-to-center distance between your pupils, or interpupillary distance (IPD). If you wear glasses, your optometrist has this number on file for you. Look at something, and the images each eye sees are slightly offset from each other. Your brain processes these two images so that you perceive the world in three dimensions.
An anaglyph is an image that consists of two superimposed images, each printed in a different color. The filters in the viewer’s glasses correspond to these colors. Each eye gets a color. When viewing the image without the glasses, you see the image with a distracting red or magenta and blue-green offset image on either side. When you wear the glasses, the images are filtered so that each eye sees only one, and your brain combines the two images as usual. The result should be a decent approximation of a 3D image - although it gives some people a headache.
The important thing when making an anaglyph is to chose your separation colors wisely. Look at any color filter 3D glasses and you’ll notice they’re all some variation of reds or pinks on one side, and blue-greens on the other. I have versions in red/blue, red/cyan and magenta/green (and honestly, I think the blue and the cyan are basically the same). These pairs have little to no overlap - there’s no red in the blue or magenta in the green, so the filter can completely block the undesired image while the desired version passes through. If you were to try this with a red/orange pair, for example, you’d be very disappointed in the results.
So, if you pick colors that aren’t completely separated, or colors that don’t quite match the filters in your glasses, you may see stray ghost images that appear as distracting outlines and fuzziness in your 3D image. The people who made 1922’s Power of Love or 1983’s Jaws 3D would have agonized over this to give their audiences as perfect an experience as possible, we DIYers will have to be a bit more forgiving.
Depending on our resources, we could have proper 3D glasses, some random color filters purchased online, or even make a filter by rubbing a Sharpie marker on some transparent film. Results will vary.
The process that was elusive and highly technical in times past is actually pretty simple to demonstrate now - IF you have access to some image processing software. Making them can be easy - making them well of course takes a bit more effort. But classroom demo quality? Can-do.
In the next few posts, we’ll build up to making our own anaglyphs and stereograms, starting with a demonstration of color filtering so simple, we can do it with classroom markers.
Anaglyphs - full color
Stereograms
** What was the difference between retro red/blue 3D glasses and the RealD 3D glasses? The RealD glasses used the same concept but instead of color filters, it used polarizing filters. The result was a great improvement but not so great that we all agreed to make all movies and tv 3D in the early 2000s. As a society we collectively decided to wait for VR and honestly, that was a solid choice.