The Different types of 3D

3D , (or if you read my last post S3D) comes in many different forms.  Not wanting to bore you (too late!), but here’s a brief explanation of the many, many different types:

Red/Green AnaglyphRed/Green cardboard glasses, very cheap to make

This is the traditional 50s ‘B’ movie 3D with the cardboard glasses.   It made a reappearance in the 80’s in films like Jaws 3D, but it died.   Why?  Because it’s useless, between people with poor eyesight and people who suffer from colour-blindness, nearly 50% of the population experienced no effect from looking at a red/green film while wearing red/green glasses. 

Colour Code or blue/orangeChuck: "Chuck vs the third dimension"

This is the 21st Century version of red/green.  Basically some bright spark noted that with the right shade of blue and the right shade of orange, the mixed image appears almost normal.  So anyone watching the video without glasses is still able to enjoy it.  And most people don’t have blue/orange colour-blindness.     A few years ago an episode of Chuck was filmed using color-code.  Still doesn’t really work though.

Now we move onto the proper stuff:

Passive LinearPassive Linear glasses

This setup involves two projectors each with a polarising  filter on them.  One only shows light in a vertical plane, the other only shows light in a horizontal plane.  Everyone wears glasses with matching filters and the projectors need a very expensive, very flat, silver screen to reflect the light in those polarisations.   The glasses are cheap-ish (£2 each) and the effect works, even sometimes for me!  The room has to be dark to work properly too.

We have a passive system in school, from a company called Inition.  It’s great and really very easy to use.  Although Passive Linear cannot be used directly with all the new blu-ray 3D stuff.  grrrr!

Passive Circular

Same thing as linear, but slightly more expensive as the filters use circular polarisation.   The big difference is that users can twist their heads and the effect still works.

Dolby Color Code 3D

A truly cool system (because it works for me, obviously)  It’s a variation on the Colour Code blue/orange system but it is refined and uses glass lenses.  The result is that for a viewer not wearing glasses, the picture is perfectly normal, but when you were the heavy and quite expensive (about £40 each).  You only need one projector and a regular screen.

Imax Digital 3D

Supposedly Imax is similar to Dolby, but the effect was completely lost on me.   A number of forum posts on the internet suggest I’m not the only one left out in the cold by this system.  The glasses are much cheaper too, which is why so many cinemas have opted for this system. 😦

Active Shutter

The daddy.  Quite frankly.  Unless of course you suffer from headaches or eyestrain.  A Infra-Red signal from a 3D-ready projector or TV switches on/off tiny LCD screens in the glasses.  Flickering 120 times per second, the human eye doesn’t register the flickering but instead only sees one view.   Clever, but heavy and expensive (£80 per pair of glasses).  I’ve seen this work with a lot of light in the room and a very poor quality screen.

Nintendo 3DS

3D that doesn’t come out at you.  It’s billed as glasses-less 3D, because the view shown is worked out for the screen by the console tracking your eyes.  If you were looking into a room through a window, you would see different parts of the room depending where you stood.  Nintendo’s head tracking works in the same way.  Very cool.   Some TVs are offering glasses-less 3D and it’s presumed it will work in the same manner.

So there you are, a quick bluffers guide to 3D (or S3D, I really must start using this term). What does all this mean though?

Well realistically if you want 3D in your school the only two options are passive or active shutter.

Active Shutter is cheaper to get and portable. But the maintenance costs of replacing the glasses puts a lot of people off. Oh and works with 3D blu-ray.

Passive is expensive to get and has to be in a fixed position in a controlled environment, but it is really cheap to look after.

Of course once you get 3D, you need some content.  But that’s another story, or post at least.


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