Unlike the memories provided by movies, film itself is an ethereal thing. That’s the message of the Library of Congress Film Preservation Tour, which stops at the Alamo Theatre in Bucksport for nine days, beginning Dec. 2. People looking at walls of movies at a video store would think most films already had been preserved for posterity, but they would be wrong.

“People think that all the films are taken care of; if it’s on video, it must be safe,” said Karan Sheldon, co-founder of Northeast Historic Film, the regional archive that is housed at the Alamo. “They also think that with digital magic, it must be really easy to preserve the films.”

The National Film Foundation estimates that fewer than 20 percent of U.S. feature films from the 1920s survive in complete form. Only half of American features produced before 1950 remain. It’s impossible to estimate how many short films, documentaries and independently produced works have been lost.

That’s why Congress passed the National Film Preservation Act in 1988, which established the National Film Registry and the National Film Preservation Board.

The board advises the Librarian of Congress in its selection of 25 motion pictures added to the Registry each year. These films, which now number 275, are chosen on the basis of their cultural, historic and aesthetic importance.

Sheldon, who serves on the FNPB, said there aren’t viewing copies available for many of these cultural touchstones.

For the tour, 37 films from the registry were made available, with local groups selecting those they wanted to show.

Studios and archives have struck new prints of these films, and all screening fees are waived, so the proceeds go toward preservation efforts.

The tour will be stopping in all 50 states, with the films shown on large screens, preferably in restored theaters.

“This is important, because otherwise people wouldn’t get to see these films as they were meant to be seen,” Sheldon said. “It’s a range of films that have had an impact on our culture. The Library of Congress wanted people to see them, because his message is that they are at risk.”

For example, NHF almost was unable to show “Dr. Strangelove,” set for Dec. 6, because the touring copy was worn out to the point of being unusable. Fortunately, the movie’s studio was willing to create a new print.

Also, Maine resident Mary Lampson, film editor for “Harlan County, USA,” wanted to do a workshop for students. NHF finally tracked down the one surviving print of the film, which will be shipped from Amsterdam, where it is being shown the previous week.

The Alamo will be the tour’s lone stop in Maine, thanks to a previous relationship with the Library of Congress.

“The Library of Congress is very interested in a national collection of moving images, and has a good deal of it there,” Sheldon explained.

“They also believe that regional archives help to make up the rest of it.”

The Bucksport archive also will show several of its own films during the special event. Being unveiled Dec. 8 will be “The Land of the Great Spirit.”

It’s a color Prizma film of American Indians from 1919 that was discovered at the East Stoneham Knights of Pythias Hiawatha hall last year.

With video versions of some of the movies to be shown in local video stores, why see them at the theater?

“There’s the shared experience, the energy of being with other people reacting to what’s being shown,” Sheldon said. “Also the films diminish in video and audio quality in other formats.”

Sheldon hopes the tour stop will open people’s eyes to the need for film preservation.

“We’re preserving not just Hollywood movies, but independent films and people’s personal lives,” she said. “Film preservation is fragile, tenuous, scary and expensive, especially the digital kind.”

Tour schedule:

Dec. 2, 12:15 p.m., “Big Business,” free children’s show with live accompaniment by Clayton Smith.

Dec. 3, John Ford Day, presented by Don McLean, 4 p.m., “My Darling Clementine,” 7 p.m., “The Searchers.”

Dec. 4, 6:30 p.m., “Ninotchka,” 9 p.m., “Chinatown.”

Dec. 5, 1:30 p.m., free showing of “Evangeline”, 7 p.m., “The Great Train Robbery,” “Gertie the Dinosaur,” “Within the Gates,” 9 p.m., “The Cheat,” the latter two shows presented by Tricia Welsch of Bowdoin College and with live accompaniment by Sylvia Moscovitz.

Dec. 6, 1:30 p.m., “Dr. Strangelove,” free, 7 p.m., “All Quiet on the Western Front.”

Dec. 7, 2 p.m., “Harlan County, USA,” with student workshop led by Mary Lampson, the film’s editor, 7 p.m., “On the Waterfront.”

Dec. 8, Film preservation gala, “The Land of the Great Spirit,” “The Making of an American,” “All is Not Gold That Glitters,” “Cherryfield 1938.”

Dec. 9, 7 p.m., “Out of the Past,” 9 p.m., “Raging Bull,” presented by Eric Schaefer of Emerson College.

Dec. 10, 2 p.m., “Jammin’ the Blues,” “What’s Opera Doc?,” “Duck Soup,” 4 p.m., “Meshes of the Afternoon,” “Eaux d’Artifice,” “Castro Street,” “the March of Time,” “The River,” both presented by Eithne Johnson of Wellesley College; 7 p.m., “Sunrise.”

Unless otherwise indicated, tickets are $6, and $4 for NHF members, seniors and students. For reservations, call 469-0924, or visit the Alamo Theatre box office.

Renovations under way at Alamo Theatre

The Alamo Theatre is undergoing a series of renovations to improve the movie-going experience for its patrons.

A new curtain and masking, which will allow the screen to be the right shape for each film, should be in place by month’s end.

A new Dolby system will allow newer films to be heard in digital sound, while an infrared sound system will be used on older prints.

In addition, an assisted-listening system is being installed. An infrared pulse is beamed off the screen and back to headsets worn by patrons, who can adjust the volume to their comfort level.

Also, new seating will be installed by February, replacing those bought for $2 apiece from the former Powers Theatre in Caribou.

Many of these renovations were made possible by a $100,000 donation by Pentagoet, a Portland-based foundation.

A colorful electric sign will be added to the 1916 cinema in two stages. The reader board, which advertises film offerings, should be erected this month. The electric sign, with the word “Alamo” and the Northeast Historic Film logo, will be completed this spring.