Have you ever seen a 3D movie? They’re pretty cool, aren’t they? Did you find yourself reaching out to “touch” things that looked like they were hovering right in front of you? We’re in the Golden Age of summer blockbuster cinema right now, but realistically, this is just the beginning. Every new action-heavy, “genre” film (think superhero, fantasy, adventure films) seems to get the 3-D treatment these days – something that was extremely rare even a decade ago. The film that really set the bar in terms of 3-D was Avatar (2009), which went on to become the highest-grossing film worldwide. Since then, movies have continued to take advantage of this new technology, perhaps due to a combination of enhancing the movie-watching experience and increasing their earnings. So, what exactly does watching a movie in 3-D involve? What is it about this fascinating technology that entices movie-going audiences around the world?

3D stands for three-dimensional. “Regular” movies are 2D, or two-dimensional. What are dimensions, and what’s the difference? Dimensions are properties of space. They refer to an extension in a particular direction. For example, two-dimensional (2D) images have two dimensions: length and width. Think of a picture drawn on a piece of paper. The paper has length and width. Many things in the real world, however, have three dimensions. The third dimension is depth. Think of a cube. Not only does it have length and width, but it also has depth. Similarly, when you watch a movie, the screen is two-dimensional. It has length and width, but not depth. That’s why “regular” 2D movies appear as if all the action is happening up there on the big screen. 3D movies, on the other hand, add depth and make you feel like you’re part of the experience. You see cars flying toward you or snowflakes floating in the air all around you. Isn’t modern technology amazing? How do they do that?

Try these simple experiments to test your binocular vision. Hold one arm straight out in front of you with your thumb pointing up. Close one eye and stare at your thumb. Now close the other eye. What do you see? As you close one eye and then the other, you should see your thumb appear to move slightly against the background. Think binocular vision doesn’t make much of a difference? Grab a ball and ask a friend to toss it to you. Practice catching the ball a couple of times. Then, keep one eye closed and try to catch the ball. Do you notice how much harder it is to gauge distance and catch the ball? Scientists have a fancy word for how your eyes and your brain work together to see in three dimensions. It’s called stereoscopy or stereoscopic vision. Stereoscopy is what modern 3D technology tries to duplicate.

Basically, movies try to mimic the stereoscopic capabilities of human eyes and the hardest part for 3D movie makers is getting a camera to do the same thing so that they have the right images to send to your eyes via the movie screen. To get a good 3D image, you have to have two versions of the same image filmed from the exact angle as your eyes would see it. To accomplish this, filmmakers use special film rigs that use two cameras bolted into position to mimic human eye position. The lens capturing images meant for the left eye would have a red filter and the lens doing the same for the right eye would have a blue/cyan filter. 

The cameras used for shooting 3-D films have two lenses placed adjacent to each other, closely resembling a pair of human eyes. Alternatively, movies shot using regular 2-D cameras can be converted to 3-D in post-production using special 2-D to 3-D conversion software. Visual effects would have to be created using computer-generated imagery (CGI) to accomplish the same effect. To make an animated movie in 3D, animators do basically the same thing. They create two versions of each individual picture to duplicate the perspective of each individual eye. Although it’s easier to get perfect images, it also takes a lot of extra time to create all the extra images.

This arrangement enables two sets of images to be captured, each with a slightly different perspective. In the cinema, both sets of images are merged and projected simultaneously onto the screen, could be viewed as one image using red-cyan glasses, commonly known as 3-D glasses. Due to their use of the same two opposing colors used as filter lenses to capture the images, each lens of the anaglyph 3-D glasses allows only the corresponding color image into the eye. Therefore, each eye is viewing a different perspective of the virtual object, similar to how a real object would be viewed. This stereoscopic 3-D effect is known as anaglyph 3-D. However, there was a downside to the anaglyph 3-D method, namely that a movie could not be captured and viewed in full color. This finally brings us to the most popular and ultra-modern 3-D technology used by leaders in the field, such as IMAX.

There are several different types of 3D technology in use today, but they basically do the same thing. Depending upon the exact type of technology used, the 3D glasses you wear will either use special shutters, color filters, or polarized lenses to receive the images. Your brain takes care of the rest! For example, older (and some newer) 3D movies have to be viewed through special red and blue (sometimes red and green) glasses. Images are projected in those colors — red and blue — and the special glasses make sure each eye only receives one of the images. As always, your brain puts the 3D effect together. Current movies use polarized glasses that take advantage of the fact that light can be polarized, or given different orientations. Newer 3D glasses with polarized lenses don’t need separate colors and can give a much more lifelike experience. Your incredible brain does all this 3D processing automatically. 

As we, Galalite Screens celebrates 60 years of a successful journey in providing innovative cinema screen technologies, we collaborate with Sightsavers India for the campaign called ImagineSee.org. The main purpose of this campaign is to aid the visually impaired children and to share awareness about preventive blindness. We welcome you to join this initiative, together let’s make them see too.