Prior to 1952 and the introduction of color film stocks, color movies were produced using a Technicolor camera which exposed three separate black and white negatives simultaneously to the red, green and blue colors of the spectrum. Prints from these negatives were made using the Dye Transfer technique. Disney used the three-strip process until around 1937 when the Studio was the first to use a modified camera process such that instead of having three separate Red-Green-Blue reels of film, Sequential Exposure shoots each frame three times on a single strip of black and white film through an RGB color wheel(e.g., R1-G1-B1 / R2-G2-B2 /R3-G3-B3 and so on). The SE process was then used primarily for animation on approximately 60 titles and the “True Life Adventure Series” which combined a fine-grain dupe of 16mm live action film with animation. Much lower production cost and easier exposure latitude of Kodak’s color stocks led to a ‘vacation’ of sorts for the SE process.
In the mid-90’s, with the push into Computer Aided Animation/CGI and birth of Digital Film Recording, the Animation Camera department decided to revisit SE photography to take advantage of the faster recording speed on B&W film and Techinicolor’s high-speed step-printing. The side benefit would be to have an archival quality negative immediately without generational loss through the dupe process. SE was then used for production or archiving for nearly all of the animated features and continues through the present. This technique was then applied to the task of protecting all the Disney Films in the U.S. Library of Congress starting with our 35mm Nitrate negatives.
“Disney was a pioneer in this method of photography and over time we have learned through our restoration efforts that SE photography provides greater stability and re-registration,” said Theo Gluck, Disney’s Director of Library Restoration.
All this leads us to apply the SE technique to the long-term archival storage of all our digitally finished motion pictures. For decades, the Studios would have the film labs create “YCM Separation Masters” of their finished films onto color dupe stock. The key advantages to the SE method for Archival Protection are that the registration process is far easier and more accurate as it uses a single piece of 35mm film as its storage medium, and color accuracy is ensured because silver-based B&W film does not fade like color dupe stock.
We use SE’s to augment our digital archives as a measure of disaster recovery and to ensure our films are future-proofed. Digital archives(both magnetic and optical) are relatively new, and there is some uncertainty with long-term stability. As such, converting our digitally finished motion pictures to film is one of the most important steps we can take today to preserve our library.
The DDSS Film and Digital Services group utilizes four ARRI Laser Film Recorders to produce SE negatives. In addition to preserving the new Disney blockbusters going forward, SE’s continue to be created to preserve the Studio’s most beloved and important library titles so generation after generation can continue to enjoy them.