An obscure German folk tale about a beautiful woman undermined by her evil stepmother before becoming housekeeper to seven miners was perhaps an unlikely hit in early 20th-century America. But during the California Christmas of 1937, Walt Disney’s romantic retelling of the Snow White story proved a game-changer for popular culture.

Now, 80 years after his animation Snow White and the Seven Dwarfs enjoyed its premiere on 21 December 1937 at the Carthay Circle Theatre in Los Angeles, rare original drawings from the film are to be sold at auction. The animated film, which was the first full-length feature from Disney’s studio, went on to make an unprecedented $8m during its initial release, and nine years ago was named the greatest American animated film of all time by the American Film Institute.

On Thursday, 20 familiar images are to go on sale at the Swann Galleries in New York. Each has been preserved in the pages of a carefully compiled scrapbook thought to have belonged to Disney artist Ingeborg Willy, an “inker” who worked at the studios between 1936 and the winter of 1941.

Using cotton gloves, she would carefully lay a sheet of celluloid over the graphite drawings and trace the outlines in ink, before the drawings would go to the painters to be finalised. Included in the scrapbook are single “cel” drawings in graphite or coloured pencil on paper, along with a few inked pictures on celluloid, and they feature the recognisable outlines of Snow White, the dwarfs and several woodland creatures. Willy also kept invitations to staff events, newspaper clippings, camera directions, as well as photographs of her colleagues and friends. Also included is a single page of director’s notes titled “Special Notes to EFX”, thought to be in Disney’s own hand. The collected images are expected to fetch $7,000 to $10,000. In 2012 a similar scrapbook owned by Willy was acquired by the Walt Disney Family Museum.

Artwork from Snow White is judged among the most precious in the Disney canon because of the film’s impact on the movie industry. In a succession of deft brush strokes it created an alternative, colourful fairytale world that Hollywood animators, rather like the seven dwarfs, have been mining lucratively ever since.

Disney is believed to have been drawn to the fairy story, which had already been turned into a Broadway show, because of the humorous possibilities of the dwarfs. Their names and personalities are not mentioned in the Brothers Grimm’s 1812 version but Disney had the idea that they should have distinctive personalities. Early suggested names included the unappealing Jumpy, Hickey, Wheezy, Baldy, Stuffy, Tubby and Burpy.

At the 11th Academy Awards ceremony, Disney was awarded an honorary Oscar, while his film was nominated for best musical score the previous year. In 1989 the United States Library of Congress recognised the film as “culturally, historically, or aesthetically significant” and selected it for preservation in the National Film Registry.

An ‘inked’ image from the scrapbook of Ingeborg Willy. Photograph: © Disney Studios/Courtesy of Swann Auction Galleries

Yet preserving the many individual cels created to bring the story to the screen in the Disney studio has proved a puzzle. Many are now being studied in the science department of the Getty Conservation Institute (GCI), in the Los Angeles hills. Researchers, supervised by British scientist Tom Learner, have made a series of recent technical breakthroughs.

One of the main challenges was to find a way to stop the painted images peeling away from the ageing celluloid. In 2009 a curator at the Disney Animation Research Library first noticed that many of the transparent cels were degrading. The celluloid was buckling and yellowing, while, most worryingly, some of the paint was starting to flake away, or delaminate.

Scientists at the GCI, who work on a broad range of cultural heritage, including fine art masterpieces and archaeological sites, were asked to help find ways to restore the animation cels from several films, including Snow White and the Seven Dwarfs and more recent hits such as 1989’s The Little Mermaid.

GCI’s senior scientist Michael Schilling, who has also worked on treasure found in Egyptian tombs, was assigned to the project and his team has now developed, with some success, a process using raised relative humidity to allow the paint to re-attach.

“There’s a drawing on one side and paint on the opposite side,” Schilling told the Frame website at the beginning of his work. “So you can’t lay the cel on to anything safely, because whatever you lay it on to is going to stick to either the paint or the drawing.”

As it takes 24 cels to produce just a second of animation, there is no shortage of work, and the contract between the GCI and Disney will go on for a further two years. Luckily, the paint formulations used by the original Disney artists have proved resilient. After detailed research, the studio opted to use a number of unique formulations that differed from those used by animators working during the same period.

Disney also insisted the films were stored in a room called the “morgue” – a climate-controlled sunless space underneath the original studios. The archives were moved to Disney’s current site in Glendale in 1989 and are still regularly consulted by animators.