Background The film rights to the book
Mrs. Frisby and the Rats of NIMH had reportedly been offered to
Walt Disney Productions in 1972, but they were turned down.
The Secret of NIMH was the first
feature film to be
directed by
Don Bluth. On September 13, 1979, Bluth, fellow animators
Gary Goldman and
John Pomeroy and eight other animation staff left the feature animation department at Disney to set up their own independent studio,
Don Bluth Productions. The studio worked, at first, out of Bluth's house and garage, but moved to a two-story, facility in
Studio City, California, several months later. While they were still working at Disney, they produced the 27-minute short film
Banjo the Woodpile Cat (1979) as a side project to gain other production skills that the company and their animation program were not addressing. Bluth asked
Ron W. Miller,
Walt Disney's son-in-law and the president and CEO of the company at the time, to view
Banjo, but Miller declined. As Goldman recalled, "that pulled the enthusiasm rug out from under us. We had hoped that the studio might like what we were doing and agree to buy the film and allow us to finish the short film in the studio, which would allow us to recoup what we had spent in terms of money and the many hours that we and the other members of the team had invested in the film". He gave the book to Bluth for him to read and make a film out of after Bluth finished the animation direction of ''
Pete's Dragon'' (1977). Bluth later showed the novel to Disney animation director
Wolfgang Reitherman, who turned down Bluth's offers to make a film based on the book, explaining that Disney has already a mouse named
Mickey Mouse and they had recently made a similar film about mice named
The Rescuers (1977). However, Bluth also presented the novel to the other staff that would work for Don Bluth Productions later on and they all loved it. Two months later, former Disney executive James L. Stewart, who now had started
Aurora Productions, called Goldman and told him about Anderson's idea of making a film based on
NIMH. This was most apparent in the magic
amulet given to Mrs. Brisby, which was meant to be a visual representation of her character's internal power, something harder to show on film. The object was also meant to introduce a
spiritual aspect to the plot, with the director remarking: "The stone or amulet is just a method of letting the audience know that Mrs. Brisby has found 'Courage of the Heart'. Magic? Maybe. Spiritual? Yes". The studio set out with the explicit goal in mind of returning feature animation to its "
golden era", concentrating on strong characters and story and experimenting with unusual and often more labor-intensive animation techniques. Bluth believed that older techniques were being abandoned in favor of lower production costs and that the only way that animation could survive was to continue
traditional production methods. Among the techniques experimented with on
The Secret of NIMH were
rotoscoping, multiple passes on the camera to achieve transparent shadows, backlit animation (where animated
mattes are shot with light shining through
color gels to produce glowing areas for artificial light and fire effects), and multiple color palettes for characters to fit in different lighting situations, from daylight, to night, to warm environments, to underwater. Mrs. Brisby had 46 different lighting situations; therefore there were 46 different color palettes, or lists of color, for her. Two modern, computerized versions of the
multiplane camera were also manufactured for this production. Objects like the bird cage that Mrs. Brisby escapes from, and the boats used by the rats, were made as physical models, painted and photographed, and eventually xeroxed onto animation cels which were then painted. Also Mrs. Brisby's home and several other locations were built as a physical model and photographed from different angles. These pictures were used as reference for the layout artists. To achieve the film's detailed full animation while keeping to the tight budget, the studio strove to maximize its use of time and resources. The crew often worked long hours with no immediate financial reward (though they were offered a cut of the film's profits, a practice common for producers, directors and stars of live action films, but never before offered to artists on an animated feature). Producer Gary Goldman recalled working 110-hour weeks during the final six months of production. Around 100 in-house staff worked on the film, with the labor-intensive
cel painting farmed out to 45 people working from home. Many minor roles, including incidental and crowd voice work, were filled in by the in-house staff. The final cost of the film was $6.385 million. The producers, Bluth, Goldman and Pomeroy and the executive producers at Aurora mortgaged their homes collectively for $700,000 to complete the film, with the understanding that their investment would be the first to be repaid. The film was the sixth animated feature to be presented in the
Dolby Stereo sound system. In animating Justin and Jenner's sword fight, the animators referenced similar sequences in films such as
The Adventures of Robin Hood (1938) and
The Vikings (1958). ==Music==