When you walk into a movie theater, you probably don’t think much about what’s going on in the projection booth.

You picked the theater because it was conveniently located, or because it was showing the movie you wanted to see at the time you wanted to see it, or perhaps because it had oversize comfortable seating. You went because you wanted to see a movie — a story told in sound and pictures — not a demonstration of projector technology.

But a movie shown in a theater isn’t just a movie. It’s a presentation.

Just as the arrangement of food on a plate is an important part of a restaurant experience, and the framing and placement of paintings is integral to a museum visit, the way a movie is projected can have a meaningful impact on your theatrical experience. Great projection can make a movie sharper, more colorful, more vivid and engaging — while poor projection can be a movie-ruining distraction.

Understanding the nuances of movie projection, and the different projection options available to moviegoers, can help you make the most of the cinematic experience you pay good money for. But understanding those nuances means understanding how projection has changed over the years, and how technological advances have affected not only what we see on the screen but how it gets on that screen.

The history of movies is a history of film technology

Today, most movies and even television are widescreen extravaganzas, designed to fill up the space on modern screens and high-definition televisions. But in the earliest days of motion pictures, movies were typically projected on 35mm film, meaning that the film reel itself was 35mm wide. The 35mm reel was adopted as an international standard in 1909.

These early films were shown in a boxy 1.33:1 aspect ratio — not quite a square, but without the scope that is the standard today. (Since this will come up frequently, a film’s “aspect ratio” is its shape, expressed as width:height. So a 1.33:1 ratio is 1.33 feet wide for every foot high it is, and is also sometimes written as 4:3. Read much more about this here.)

That ratio changed slightly with the advent of sound on film, because filmmakers had to make room on the film reel for the soundtrack. (In the analog world, information always takes up physical space.) That pushed the ratio to something more like 1.37:1.

A few filmmakers also experimented with wider formats during this time: French filmmaker Abel Gance, for example, worked in a format dubbed Polyvision, which could show panoramic images as wide as 4:1. But for the most part, the ratio stayed right around 1.37:1 until after World War II, when competition from television spurred innovation from filmmakers and theater owners.

As Chris Robinson, a film professor at the University of Arkansas Little Rock who studies the history of film projection and production technology, tells me, “Studios were interested in trying to give people something that they won’t see at home — something a little more spectacular, a little bigger.”

Suddenly the screen started to expand. The postwar period saw experiments with technologies like Cinerama, which used three projectors running simultaneously to fill out a massive, wraparound screen, as well as with widescreen formats like CinemaScope, which used anamorphic lenses that allowed filmmakers to capture a picture across a complete 35mm frame and then stretch it out during the projection process. That let directors craft images that were as wide as 2.66:1.

Other filmmakers began to experiment with shooting and projecting films in 70mm — double the width of traditional film reels. Films like Ben Hur, 2001: A Space Odyssey, and Lawrence of Arabia used Panavision technology, which not only allowed for a widescreen presentation but also captured images of much greater resolution, offering an immense sense of scale and detail. This gave the epics of the 1950s and ’60s their truly epic quality.

But after this period of experimentation, Hollywood settled into a relatively stable equilibrium, in which most movies were shot and projected on 35mm film and shown either in “scope” at 2.35:1 (or sometimes 2.39:1) or in the more conventional ratio of 1.85:1. All were wider than the old 1.37:1 standard, but not as wide as the experimental formats of the ’50s and ’60s.

But the evolution of projection isn’t just limited to the size of the film being shot on. During the 1970s, theater owners switched from showing movies on reels, which required projectionists to cue up segments of movies on two separate projectors and switch between them throughout the film, to platters, which allowed projectionists to connect all the reels of a film together on a massive spool that could play through a single projector. But otherwise, the system stayed relatively stable.

However, the move to platters exacerbated one of the drawbacks to analog film: As a physical medium, it could degrade or be damaged. The new process was easier on projectionists, who no longer had to feed two cameras and time the switches between them, but platters were rougher on the film prints themselves, making them more likely to be scratched or dirtied. In the days of analog projection, one of the biggest reasons to see a movie on opening weekend was that the print was more likely to be pristine.

Enter the digital evolution

For those, like me, who grew up watching movies during the 1980s and ’90s, the 35mm standard, in one of two aspect ratios, accounted for nearly every movie you saw. It was the standard, and it defined theatrical presentation during the first decades of the blockbuster era.

But that standard began to erode at the end of the 20th century as filmmakers began to integrate digital technology, in the form of computer-generated special effects and editing, into their workflow.

More precisely, the standard began to erode in June of 1999, when George Lucas conducted the first all-digital screenings of a major motion picture: Star Wars: Episode 1 — The Phantom Menace. Lucas wasn’t quite the first filmmaker to embrace digital projection — The Last Broadcast, a dirt-cheap found-footage horror film, had been projected digitally in October 1998 — but he was the most prominent.

Digital projection didn’t catch on immediately, and throughout the 2000s, Lucas expressed frustration with the slow pace of the transition. But the die was cast. As film historian David Bordwell recounts in his book Pandora’s Box: Films, Files, and the Future of Movies, in the year 2000 there were just 30 movie theaters set up with digital screens in the world. A decade later, there were more than 36,000.

The transformation of the multiplex was the result of a confluence of efforts from different branches of the film industry. Technology-focused filmmakers such as Lucas and James Cameron, whose 2009 film Avatar became a major inflection point in the rise of digital projection, were vocal proponents of the evolution to digital. A group of major movie studios — Disney, Fox, Paramount, Sony Pictures Entertainment, Universal, and Warner Bros. — set up a consortium called the Digital Cinema Initiative to develop industry standards for digital projection technology in the mid-’00s.

Theater owners themselves, who initially balked at the expense of digital projection, finally came around when it became clear that digital projection could add to their bottom lines, reducing labor costs by cutting out pricey skilled projectionists and allowing theaters to charge more for digital 3D movies like Avatar.

The transformation of the multiplex coincided with the transformation of the way films were shot. For years, cinematographers — the camera specialists who oversee a movie’s photography — had expressed skepticism about the ability of digital cameras to compete with film. Compared with 35mm, early digital cameras weren’t light- or color-sensitive enough, and didn’t provide the same level of resolution.

But as Bordwell notes in his book, by the beginning of the 2010s, even legendary cinematographers like Roger Deakins could be found praising digital as comparable to or even better than film. It looked like digital had won the format war, and analog filmmaking and projection was dead.

For the love of film

But just as it looked like analog was done for, film started making a comeback — thanks, again, to the determination of a small group of filmmakers.

Christopher Nolan, in particular, led the charge, eschewing digital effects where possible and continuing to shoot on film — not only 35mm but 70mm IMAX as well. For The Dark Knight Rises and Interstellar, Nolan staged screenings using 70mm prints, and employed multiple aspect ratios within the film, switching between them depending on the scene. His next film, the forthcoming Dunkirk, was shot entirely on 70mm.

Nolan isn’t the only contemporary director embracing 70mm. Quentin Tarantino shot his 2015 film The Hateful Eight on 70mm, and set up limited “roadshow” screenings across the country using ancient projectors, many of which had to be cobbled together from spare parts, to present the film in a rare, ultra-wide aspect ratio of 2.76:1. The Hateful Eight roadshow was a throwback to the days of analog spectacle — a unique film-only experience designed to lure viewers out of their homes and away from their televisions.

The renewed interest in throwback formats can also be seen in some of 2016’s more high-profile releases: La La Land was shot in CinemaScope and projected in a slightly wider 2.55:1 aspect ratio as a reference to the movie musicals of the 1950s, and Jackie was shot on Super 16mm (a little under half the size of 35mm), in order to achieve a look that resembled archive footage. Even Deakins returned to film for the Coen brothers’ Hail, Caesar — with reservations — and says the Coens are considering continuing with using film over digital in their next film.

Indeed, Robinson, the Arkansas film professor, argues that we are now in a “return to that era,” in which studios, filmmakers, and theater owners have once again started to experiment with projection technology in response to competition from home theaters and streaming sites such as Netflix.

Today’s 4K televisions, which enable the display of images at four times the resolution of typical HD screens, have the potential to provide images that are higher resolution than the 2K projectors that are found in many theaters. So just as in the heyday of Cinemascope and Cinerama, when theaters employed newer, bigger formats in order to draw viewers away from their TVs, theaters are now looking for ways to create experiences that can’t be had at home. In addition to analog experimentation, theaters are experimenting with digital variants such as IMAX, 3D, and laser projectors, which provide a far brighter and more vividly colorful picture than ordinary digital projection.

How to make the most of the modern moviegoing experience

The result of this renewed experimentation is that there’s more variety in the ways movies are shot and projected than ever before, and more choices for both filmmakers and moviegoers. And that can lead to confusion.

Take a movie like Batman v Superman: Dawn of Justice. In addition to seeing it in conventional digital projection, either 2D or 3D, you also had the choice to see it in several “premium formats.” Some theaters showed it in IMAX 70mm, using 70mm prints projected onto large-format IMAX screens. You could also see it in laser-projected IMAX 3D, or in laser-projected IMAX 2D.

The profusion of formats has created challenges for theaters and moviegoers alike — some theaters have reportedly struggled to manage the transition between 3D and 2D projection, making 2D films dull and dark in the process.

Figuring out exactly how to see a movie these days can take a bit of work, but Robinson offered a few tips.

If you want to watch a movie in 3D, look for a theater that uses two projectors working together. The 3D effect is created by overlaying two images, which creates a “stereo” effect that gives it depth; it's the visual equivalent of two speakers working in tandem. But 3D projection is notoriously dim, and dual projection means there are two projector bulbs providing light. You can tell by looking behind you to see if there are two separate streams of light from the projection booth.

“Your primary advantage is that it is a brighter and better-lit picture,” Robinson says.

For digital screenings, look for laser projection, which dramatically improves the presentation of color. Figuring out which theaters are using which technology can require a bit of effort, but both IMAX and the AMC theater chains maintain lists of currently operating laser projectors.

You should also look for theaters that continue to offer correct “masking” — which is the practice of changing the aspect ratio of the screen by using moving curtains to frame the image. Proper masking ensures the picture fills up the entire visible screen area, making for a more fully encompassing experience, but in recent years, some theaters have dropped the practice entirely, resulting in projection that leaves unused screen white space visible to the audience.

If you can find a theater with a 4K projector, that’s usually a good sign too, Robinson says, although determining which theaters are using 4K technology can be difficult, as it’s not always advertised.

And consider seeking out theaters that are showing movies on actual film — at least when you're seeing a movie by a director who places a priority on the analog experience. There are sometimes benefits to doing so beyond the projection itself: Tarantino's Hateful Eight 70mm roadshow played a slightly different cut than the one that played in standard theaters. Nolan's Dunkirk will screen several days early in theaters projecting it in 35mm and 70mm.

Finally, whenever you can, seek out specialty theaters, like the AFI in Los Angeles or Silver Spring, Maryland, that cater to film lovers. These theaters employ trained projectionists and are focused on providing a high-quality projection experience, whatever the format.

In an era when mobile phones and laptops and streaming services make it possible to watch movies just about anywhere, the theatrical experience itself is arguably as big a reason to go out to the movies as the specific movie you're paying to see. If it’s worth making the effort to go out and see a movie, it’s worth understanding what you’re seeing — and getting the experience right.