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The Evolution of Projection Technology

January 29, 2010 4 comments

By Matthew Rick
Director/Digital Projectionist

LMS System

LMS System at Celebration! Lansing

If you have been to any one of our digitally equipped theaters or visited our website lately, you have probably seen some signs, or the DLP tag that plays before a movie, informing you of our new digital projection technology. You may have asked yourself  “What is digital projection? How does it work? How is it different?”

Projection technology has made many advances over the years that have changed the roles of theatre projectionists and the design of theatre booths while aiming to create the best possible experience for the moviegoer.

When Film Was King

My dad was a projectionist at a number of drive-in theaters in Saginaw during the late ‘60s. In those days, the light source use was a carbon-arc lamp. This consisted of two carbon rods through which a massive amount of DC electrical current passed, causing the electricity to ‘arc’ between the two, resulting in a massive amount of light, as well as heat, in a process similar to that used by welders. The ‘carbons’ would burn-down over the course of 20-minutes, and would need several replacements each show.

Projection Booth at Alpine

Alpine theatre projection booth

The film came on 20-minute reels, so each screen required two projectors to show a full length movie. The film fed into the projector from the reel of film placed on top of the projector. The projectionist threaded the film through the projector, and it would be taken up on another reel below. Each film print has what are called ‘changeover cues’ for this reason. When a reel of film reaches its end, a little circle, dot or ‘X’ appears in the upper right-hand corner of the picture. This tells the projectionist to start the motor on the next projector. Eight seconds later, another cue flashes, which is when the projectionist flips a lever or presses a foot-pedal, shutting down the first projector and changing-over to the second projector. If properly executed, the audience does not notice. If the projectionist’s timing is off, the audience notices a little jump-cut in the action of the film. If the projectionist accidentally threads the reels out of order or miss a changeover altogether – well, that would be very, very bad.

The projectionist then changed the carbons in the first projector, threaded up the next reel for the next changeover, and rewound the first reel of film. Projection booths were often hot and dirty places with little to no automation of any kind. My dad once told me about when a cooling line to one of the projectors burst, rendering it inoperative. He had to interrupt the movie over the drive-in’s loudspeaker to announce a brief intermission between reels. Every 20 minutes, he had to hurriedly re-thread the one working projector as all of the cars in the drive-in impatiently honked their horns.

Multiplexes and Automation

35mm Film

35mm movie ready to start

In the 1970s, technological advances introduced many systems still in use today. Rather than having two projectors at each auditorium, there was just one. The film still came in 20-minute reels to accommodate theaters that still use a two-projector changeover system, but we began to connect them all using a technique called “splicing” into one giant reel of film.

The reel sits on a circular table called a ‘platter’, is fed through a series of rollers, threaded through the projector, and taken up on another platter. For the next show, the projectionist can then thread the film from the second platter without rewinding anything. See this in action in the photo to the left.

The light source changed, too. Instead of carbon rods, projectors began to use high-tech bulbs that pass electricity between two pieces of tungsten encased in a bulb of xenon gas. They can run for thousands of hours before needing changing, and are air-cooled.

As theater owners started building ‘multiplexes’ with multiple screens – some with eight or more – surely each would need a platoon of projectionists! Fortunately, More automation freed projectionists to work on multiple screens simultaneously. The projectionists could now use ‘cue tape’ to mark points the film for the projector to dim the house lights down or up. The projector can turn itself off when the film is through or sound an alarm if it detects something wrong with the film. The projectionist just threads the projector when it is through, starts it up at showtime and stops by periodically to check on focus and sound. This allows one projectionist to singlehandedly run a dozen screens.

Modern Projection Booths
Today, projection booths are climate- controlled to keep the computerized equipment cool, and clean to keep dirt and dust from getting to the film. They tend to appear more institutional, with cinderblock walls and tile floors – though the digital/35mm projection team in Lansing has been working to make our booth a more lively place to work (we seem to have a very ‘eclectic’ decorating style between the nine of us).

The Digital Revolution
Playing film is a deleterious process. Similar to how playing a vinyl record eventually wears the record out from the friction of the needle, passing film through a very hot projector at 24 frames per second over and over causes wear and tear. When played on properly maintained equipment by a competent projectionist, a brand new 35mm film print can look pretty close to perfect. Over time, however, the film will develop small scratches and dust (even in the cleanest of projection booths), will shed little bits of itself, and start to look less-than-sharp.

DLP Projector

DLP Digital Projector

Digital projection suffers none of these issues. A digitally projected picture looks perfect the first time it is run, the last time it is run, and each time in between, because there is no film, and far fewer moving parts. It’s clean, durable, and reliable. Instead of coming to us on a bulky film reel and requiring splicing, the movie comes on a digitally encrypted hard drive, or sometimes via satellite.

The Current Process
When a movie arrives at the theater on a hard drive, we load it into our building’s Library Management Server – or LMS for short. This is called ‘ingesting’ the movie. Once it is ingested into our LMS, we can piece the feature together with whatever coming attractions, trailers, or advertisements we are to play during pre-show. We also input cues to control the dimming and raising of house lights, among other things. We can even use one complete movie file to show a movie on multiple screens – in fact, with the midnight showings for New Moon, we were showing the same movie on 18 screens at the same time – something impossible with film!

We now input showtimes into the computer system beforehand, so each auditorium knows when its next show is. If everything is working perfectly, a theatre shows preshow ads, then runs the pre-show and the entire movie with minimal intervention from a projectionist. Digital cinema is still a relatively new and complicated technology, though, so a projectionist still has to check on each movie to make sure that everything is running perfectly. Occasionally a computerized component malfunctions, which is why we still ALWAYS have a projectionist on-duty.

In addition to a flawless picture, increased automation and improved scheduling options, it is also a very flexible technology.  Because some movies are still only available on film – particularly independent movies and documentaries – we have several auditoriums equipped for both digital and film presentations. In the case of a show on film, the digital projector will play the pre-show and trailers, then will hand-off to the film projector, which a projectionist will adjust for focus and framing.

Digital projectors allow us to offer a lot of alternative content options to our guests. We can show DVDs and Blu-Ray discs for our ‘Celebrating the Classics’ series; we can show live sporting events in HD; we can partner with NCM Fathom to receive events via satellite – anything from the Metropolitan Opera to A Prairie Home Companion to rock concerts with a crystal-clear picture through our digital projectors.

We also have the ability to display specially-released movies in 3D, which itself is a technology worthy of its own blog post [editor’s note: coming soon!].

The Future
Digital cinema is still a new technology, which continues to develop and expand. As more theaters make the digital conversion, more programming options will be become available, so we can truly show something that will fit anybody’s interests.

What do you think the future holds for movie projection? Let us know your thoughts and questions in the comments!

Matthew Rick is a Director and Digital Projectionist at Celebration! Cinema Lansing.