who invented the 3D glasses and color sceme? are there other colors that would work?
Actually, the more sophisticated 3D glasses now use polarized lenses, with vertical polarization on one eye and horizontal polarization on the other.
Actually, actually, it’s 45 and 135, but who’s counting…
I like the LCD shutter glasses myself. Until one lens sticks, that is.
We perceive distancw using parallax based on the difference between what the right eye sees and what the left eye sees. To create a stereo image, you use a pair of cameras separated by several inches and take photos simultaneously. Then you rig up a device that sends the right-hand image to your right eye and the left-hand image to your left eye.
Red and blue glasses are the simplest method of doing this. You simply color one image red and one image blue and superimpose them into a single image. A red filter on one eye blocks all blue light and it only sees the red image, and vice versa. So the two eyes see two separate images.
These two colors work best because they are at the opposite ends of the visible spectrum. You could try other colors but it wouldn’t work quite as well. If you use green and red, for example, it’s hard to make a green ink or green light that looks completely black throug a red filter. In theory you could use narrow bandpass filters to use any two wavelengths, but that would require a special projector because normal film can only produce red, green and blue. You would need two projectors running separate films, each fitted with a narrow bandpass filter. And if you’re going to go to that trouble you might as well polarization filters instead which allows full color 3-D.
They’re not superimposed. You are missing a highly key element in the proceedure when red/blue is used. I’m sorry, I do not mean to be unkind. Allow me to offer a small correction?
The red and blue images are not superimposed. They are printed JUST SLIGHTLY offset left to right of one another. The brain makes the leap to adjust the two images, as is the case with very old Stereoopticon Viewers in the early days of moving images.
Your brain percieves the slight shift in the images. The rods and cones in the eyeball that see red and blue, see the individual tones and your brain composites them into a black and white focused image.
Your mind needs to see the focus, and does the combining inside, not at the eyeball/rod/cone level. It’s a nifty trick.
But you’re right about a part of it- each lens is colored one color only, therefore offering that eye one half of the image information needed to trick your brain into the Black and White composite.
Cartooniverse
The 3D process that produces images that use red and blue filters to create the effect is called anaglyph imaging, and it has been around since at least 1853:
Perhaps my memory deceives me, but it seems to me to be the case that the eye which looks through the red lens sees the blue image, and the eye which looks through the blue lens sees the red image.
Years ago I saw an old Canadian 3d movie, The Mask, at a theater which changed its bill every day or two. (In this era of VCRs and cable, do they still have such places?) For the opening minute or two of the first 3D segment, it seemed that everyone in the theater was fiddling with their glasses and muttering. Suddenly a voice from the back shouted: “Turn you glasses around! Turn your glasses around! The movie is printed backwards!” A moment later an entire theater-full of people went “ohhhhhh!” as the #D effect came into focus.
Maybe you had to be there.
There was a very entertaining book on the subject of 3D images published in 1982 called Amazing 3D, by Hal Morgan and Dan Symmes. I still see it now and again in bookstores. It comes with red/blue spectacles, and has pictures printed in orage and blue. They range from stereopticon images from the 19th Century, to home snapshots, to illustrations from 3D comics from the 1950s. There is a list of every 3D movie released up to that time. Morgan and Symmes do a very good job of giving a nontechnical explanation of various methods of producing 3D images: anaglyphic, polarized, steropticon, and lenticular.
Anything which is in the plane of the paper/screen is exactly superimposed. Anything which is in front of the paper/screen has red on one side, and anything behind the paper/screen has red on the other side.
It’s my understanding that it’s easier to adjust to if the image doesn’t actually cross the plane of the screen, so it’s entirely in front or entirely behind. In this case, the red and blue will never be exactly superimposed. But that’s not strictly necessary.
Oh, and which eye sees which image will depend on the background color. Through the red lens, the red image will look the same as white, and the blue image will look the same as black (reverse that for the blue lens). So if you have a black background, as is typical in movies, red lens will show red image. But if you’re doing it on paper, it’d be the reverse.
As well as showing one image to each eye, as the method above does, you can also show each image to both eyes, as long as you alternate them fast enough. Your brain will interpret this as 3D as well, but the flickering is annoying, to say the least. This site has some examples, using animated gifs.
DancingFool
Most 3D movies from the 1950s (the heyday of 3D movies) were shown in theaters with polarized filters in front of the projectors, and polarized eyeglasses on the viewers. Certainly all color 3D movies, and most black and white 3D movies. Few exhibitors used the red-blue filters.
Yes; using identical frames (apart from colour) and simply shifting one of them out of register will not produce a proper 3D effect - all that will happen is that the flat image will appear to be in front or behind the physical screen.
Of course the two images are not identical and cannot be superimposed exactly. Would “overlayed” have been a better word to use? Some parts of the image may be aligned exactly, other parts would be offset by different amounts. It’s these differences that give you the illusion of depth.
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The resulting image from red-“blue” glasses can be in color. In a surge of 3-D film interest in the '80s, I watched an old 50s 3-D movie that came out in color. I have never gotten a reasonable explanation as to how this happens. And I’ve asked top notch Vision experts. E.g., “Maybe it’s the Land effect…”
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The “blue” is not really blue. It’s halfway to green. The key is to have to opposite colors. Has nothing to do with position on spectrum.
I remember the resurgence of 3d stuff in the 80s and I remember it being explained that the glasses they handed out were red and cyan, rather than the usual red and blue and that this (allegedly) was how they got the images in colour.
This Danish company has developed an anaglyph system that allows full color, but appears virtually normal when viewed without glasses, unlike almost all other 3D systems, anaglyph, polarized, or LCD. The colors used are amber, which passes most colors, and a dark blue that conveys the depth cues. Click on “What is Colorcode 3D” on the home page, and scroll down to the lower half of the page for an explanation.
They’ve used the system to convert a 3D IMAX film (Encounters in the Third Dimension) to a single-strip 3D version that theaters with 2D projectors can show. The effect is more subtle than full-blown polarized 3D, but surprisingly good.
It doesn’t have to be opposite colors. You just need two colors that can be separated with filters. You could use 500nm (green) and 490 nm (slightly bluish green) if both the projector and the glasses have filters with 5nm bandpass.