The history of 3D glasses goes back into the 1850s, when Wilhelm Rollmann invented anaglyph images. 3D images don’t have to come from a 3D source; even the intelligent overlay of images with different color filters will do the trick. This spurred innovations in 3D glasses.

3D movies are quite common these days, with many of the latest animated films, action-packed blockbusters and horror flicks being presented with a third-dimension. The passive polarizing technology used to display 3D in most movie theaters is also similar to those found in passive 3D TVs. However, the fact that some movies are presented in several 3D formats in the theaters can be somewhat confusing.

There are several 3D formats today. RealD? Dolby 3D? IMAX 3D? XpanD 3D? Which is the best 3D format?

The two basic 3D techniques used in theaters right now are Active and Passive:

- Active-Shutter 3D glasses - (also called Liquid crystal shutter glasses) are glasses used in conjunction with a display screen to create the illusion of a three dimensional image, an example of stereoscopy. Each eye's glass contains a liquid crystal layer which has the property of becoming dark when voltage is applied, being otherwise transparent. The glasses are controlled by an infrared, radio frequency, DLP-Link or Bluetooth transmitter that sends a timing signal that allows the glasses to alternately darken over one eye, and then the other, in synchronization with the refresh rate of the screen. Meanwhile, the display alternately displays different perspectives for each eye, using a technique called Alternate-frame sequencing, which achieves the desired effect of each eye seeing only the image intended for it.

Advantages:

- Active-shutter glasses mostly eliminate "ghosting" which is a problem with other 3D display technologies such as RealD 3D, or Dual projector setups.

- Shutter glasses are color neutral enabling 3D viewing in the full color spectrum.

                             Disadvantages:

- Flicker can be noticeable except at very high refresh rates, as each eye is effectively receiving only half of the monitor's actual refresh rate. Modern active-shutter glasses however generally work in higher refresh rates and mostly eliminate this problem.                                                                    - Shutter glasses tend to be much more expensive than other forms of stereoscopic glasses, with most models selling for well over $100, particularly for the standard wireless models.

- Shutter glasses are also matched to the cinema and it is not possible to take them to another cinema. However, efforts are being made to create a Universal 3D Shutter Glass.

              - Polarized 3D glasses - create the illusion of three-dimensional images by restricting the light that reaches each eye, an example of stereoscopy which exploits the polarization of light.                                           To present a stereoscopic motion picture, two images are projected superimposed onto the same screen through different polarizing filters. The viewer wears low-cost eyeglasses which also contain a pair of different polarizing filters. As each filter passes only that light which is similarly polarized and blocks the light polarized in the opposite direction, each eye sees a different image. This is used to produce a three-dimensional effect by projecting the same scene into both eyes, but depicted from slightly different perspectives. Since no head tracking is involved, several people can view the stereoscopic images at the same time.

Advantages:

- (Low Cost) You can buy a pair of circular or linear polarized 3D glasses for a small amount.  This price is a little bit higher than anaglyph glasses, but they are still pretty reasonably priced.

- Another benefit polarized 3D offers is the fact that they do not use color filters in the glasses.  This means that there is no color distortion when viewing the images on the screen.

Disadvantages:

- The downside of polarized 3D comes in the cost of the projectors.  While you can use 2 low-cost networked projectors, it is sometimes difficult to get both projected images to line up exactly how you want them to.  There are systems that use one projector but the cost goes up. One example of this is the technology known as RealD.  In the case of RealD a circularly polarizing liquid crystal filter which can switch polarity many times per second is placed on front of the projector lens. Only one projector is needed, as the left and right eye images are displayed alternately. Sony features a new system called RealD XLS, which shows both circularly polarized images simultaneously: A single 4K projector displays both 2K images above each other, a special lens attachment polarizes and projects the images on top of each other.

In the US, there are four big choices in theatrical 3D projection — IMAX, RealD, Dolby 3D and Xpand.

- Dolby 3D:

- Dolby 3D uses advanced color-separation technology to deliver a superior 3D experience for next-generation laser projection. It delivers high light efficiency, crisp images, and vibrant colors to provide a superior 3D viewing experience for cinema audiences. Dolby 3D glasses for laser projection are optimized for each projector. Please contact your laser-projector manufacturer for ordering information for compatible Dolby 3D glasses.

- Passive glasses use color filtering of primary colors of light to produce a color-shifted left and right eye image which the eyewear filters out. The technology uses a single projector and a white screen.

- RealD:

-The prevalent technology in 3D cinemas worldwide comes from RealD, an American company founded in 2003. The RealD 3D format is natively digital. This means that movies have to be produced in a digital 3D format for projection on film-less digital projectors.

-Passive glasses featuring circularly polarized lenses. The images are projected from a single projector onto a silver screen.

- IMAX digital:

-Imax Digital 3D is an evolutionary improvement of the analog Imax 3D theaters that have been around since 1986.

-Passive glasses featuring linearly polarized lenses. The images are projected from two projectors onto a silver screen.

- IMAX film (large format): Passive glasses featuring linearly polarized lenses. The images are projected from two projectors onto a silver screen.

- XPAND:

-XPAND Universal 3D Glasses work with a variety of different 3D-ready television sets and computers. They also work in XPAND 3D-ready movie theaters.

-Active-shutter glasses that feature left and right lenses that open and close alternately. The images are projected from a single projector onto a white screen.

PROS:

Wearing Cinema 3D Glasses brings the audience closer to the characters - you can immerse yourself in the story with improved image quality and creates a new and different experience for many.

Very low crosstalk, no flicker, no batteries, light and cheap glasses and easy on the eyes.

Most Cinema 3D Glasses works in many 3D TV and 3D Laptops

Compared to Active Shutter Glasses, Cinema glasses do not cause much of a headache and more comfortable to wear.

CONS:

Wearing Cinema 3D Glasses can be annoying, particularly for children and glasses wearers

Many kinds of cinema 3D glasses have to be matched with the correct TV if you want to use it at home.

Occasionally, you can get headaches and eye strains.

The quality of the image can be hampered, particularly if the 3d effect is applied in post-production