By this time, Dunn had been hired as a special effects technician at RKO Radio Pictures, his tenure there lasting from 1929 to 1958.
In the early 30s, Dunn became part of the effects team responsible for the creation of the original King Kong (1933).
Many effects set-ups consisted of miniature Kong models being animated frame-by-frame in front of a rear-screen projected background plate -- of either still or live-action elements. As time progressed during animation -- when using moving footage as a background -- animators might neglect to advance the projected image (on the rear screen) to the next frame as they concentrated on Kong's movements, spoiling the illusion that the animated model and the plate coexisted in reality, thus requiring time consuming (and therefore expensive) re-takes.
Dunn saved model animators Willis O'Brien and Pete Peterson considerable work whenever possible by photographically compositing images of Fay Wray with model animation footage of Kong after all the best footage of both "elements" had been shot, eliminating the worry of rear-screen maintenance during model animation in many shots. Dunn's work also eliminated the contrast differences inherent in the use of rear-screen projection.
Dunn repeated such work for the sequel, Son of Kong, released in December 1933, and did similar optical/photographic composites for The Hunchback of Notre Dame (1939) and for Orson Welles' Citizen Kane (1941).
Today, computer technology has made it possible for a skilled amateur to create 2-D digital composites, however, in Dunn's day, such shots required a wide range of skills in order to produce believable results. Many of Dunn's optical/photographic composites, especially in less-high-profile non-fantasy films, are so flawlessly done that even today, viewers can't tell that they are special visual effects shots. In Citizen Kane, Dunn's composites open the film and many "deep-focus" shots that film historians wrongly attribute to cinematographer Gregg Toland are actually Dunn's optical composites.
Dunn also did the optical composites for the celebrated airplane-wing-dance sequence for Flying Down to Rio (1933).
Dunn worked on hundreds of films for RKO, including 1938's Bringing Up Baby, in which footage of Cary Grant, Katharine Hepburn, and a leopard, each shot separately for safety reasons, were photographically combined by Dunn.
Dunn's work became so highly sought after by other studios that he formed his own company, Film Effects of Hollywood, in 1946, working that business at the same time as working at RKO.
Dunn continued to work at RKO after Howard Hughes bought the studio. When production on the 1943 film The Outlaw was halted due to a controversy over how much of Jane Russell's bosom would be visible, Dunn resolved the situation by rephotographing Russell's close-ups with a tiny scrim inserted between the projector and camera, so as to soften the line of her cleavage.
Dunn continued to refine and improve his optical printers during all these years, garnering a technical Oscar (along with machinist Cecil Love) in 1944 for his continued exacting work.
Dunn did the optical composites and title sequence for West Side Story and the elaborate finale fire-ladder sequence at the end of Stanley Kramer's It's a Mad, Mad, Mad, Mad World (1963), which required 21 different all-color elements to be composited into final images.
Other later large-format and/or high-profile films Dunn's company did opticals for are My Fair Lady (1964), The Great Race (1965), Hawaii (1966), The Bible: In the Beginning (1966), Darling Lili (1970), and Airport (1970).
During the 3-D and CinemaScope revolution of the early 1950s, Dunn pioneered the use of optical composites using these more elaborate and difficult technical processes, inventing and refining new equipment to achieve it.
In 1956, Howard Hughes sold RKO to Lucille Ball and Desi Arnaz, who renamed the studio Desilu. Initially working on smaller projects with lower budgets, mostly filmed for TV, the special effects division of the studio was shut down in 1958 and Dunn focused on his work with his own company.
As Desilu grew as a company, even TV production required the occasional use of optical effects, especially for increasingly elaborate title sequences, and Dunn was one of several optical houses that supplied them.
In 1965, Dunn became one of four optical houses that supplied visual effects for the original classic Star Trek TV show. It was mostly Dunn who photographed the 12-foot large original Starship Enterprise model, designed by series creator Gene Roddenberry and Matt Jefferies and built by Dick Datin, Mel Keys, Venon Sion, and Volmer Jensen at Production Model Shop in Burbank, California. Dunn also generated footage that could be used by the three other optical houses involved with Star Trek - the Howard Anderson Company, Westhemier Company, and Van Der Veer Photo Effects - all necessary due to the large number of effects shots and tight weekly production schedule. Dunn continued to work on the series until its cancellation in 1969.
Dunn also specialized in optical work for special and large format films, creating the equipment necessary to do the jobs. Dunn did optical composite for several special 70mm films shown at World's Fairs, including the multi-panel tour-de-force film, A Place To Stand made for Expo 67. It was Dunn who did what his associates said was impossible, cleanly blowing up 16mm negative to 70mm prints for George Harrison's Concert For Bangladesh concert film. Dunn's later became the first facility in Hollywood that could do optical composites in the ultra-large Imax film format.
In 1985, Dunn sold his Film Effects of Hollywood company and retired from active effects work. The Hollywood office of Fuji Film occupies Film Effects' old building.
In 1983, Dunn co-wrote (with George Turner) a book on his career and the history of visual effects, The ASC Treasury of Visual Effects. In the 1990s, while in his 90s, Dunn joined with Japanese engineers in the development of a 3-D television system that used electronic virtual-reality-type glasses that auto-synched to the TV image, to create the most clear and deep 3-D images ever produced. The system was built for hospitals; surgeons in many facilities are now using the system as a key aid in sorting out the nerve-endings during micro-neurosurgery. The system was profiled on an episode of Alan Alda's Scientific American Frontiers TV series.
Always keenly interested in technology, Dunn participated in the development of digital projection for theaters. With the potential (not yet commercially realized) for creating images at a higher resolution than even 70mm film, digital projection is now in the process of supplanting film projection in theaters.
Dunn shared an Oscar win for special effects in 1949 for his work in collaboration with Willis O'Brien for the original Mighty Joe Young. In 1984, he received the Gordon E. Sawyer award from the Academy of Motion Picture Arts and Sciences, as well as being awarded Honorary Membership in The Society of Motion Picture and Television Engineers -- their highest honor.
Twice elected President of the American Society of Cinematographers, he was also elected a Governor of the Academy of Motion Picture Arts and Sciences in two different branches, and was instrumental in the formation of the Academy's Visual Effects branch.
The Linwood Dunn Theater in Hollywood was named in honor of Dunn and his innovations and contributions to the Motion Picture industry. The 286-seat state-of-the-art theater at the AMPAS' Pickford Center for Motion Picture Study on Vine Street is The Academy's newest screening facility.
After winning two final special achievement Oscars in 1979 and 1985, Dunn lived in his North Hollywood home until his death in 1998 at age 94.
1949 (22nd) for Mighty Joe Young - RKO Productions
1978 (51st) in appreciation for outstanding service and dedication in upholding the high standards of the Academy of Motion Picture Arts and Sciences
1980 (53rd) for the concept, engineering and development of the Acme-Dunn Optical Printer for motion picture special effects.
1984 (57th) Gordon E. Sawyer award