I’ll bet you all didn’t know that Technicolor films were shot on black and white film.
Sorry beforehand for the lecture.
Though Kodak color film existed in the 30s, its clarity and contrast weren’t up to the rigorous demands of large dimension projection, a necessity for movies. Enter Herbert Kalmus, and his invented technology, Technicolor.
A Technicolor camera is a simple 35mm camera with a very odd modification — behind the lens is a prism splitting the white light three ways, into red, green and blue light. Inside the camera are inserted three black and white nitrate film stocks, two back to back and one on the side, with a small mirror reflecting the light to the side film. Each strip of film recorded one color of a color picture, and the recording is on fade-proof black and white nitrate stock film.
The 3 strips are developed, and made into positives, called matrices. Each of these looks like a complete black and white film, but when examined closely, they look odd (because they only contain one color out of the total). The matrices are bathed in gelatin, and then when the silver is washed away, the gelatin adheres to the surface of the film at the exact saturation level of the color — presumably the darker the color, the more density of gelatin. And then each of the matrices is dyed one of three colors, the substractive colors yellow (for the blue record), magenta (for the green record) and cyan (for the red record). After dyeing, the matrices are pressed one at a time into prints, a process called dye-sublimation printing, at a registration precision of 1/10,000 an inch.
The original 3-strip Technicolor movies have a color palette and beauty far surpassing chemical color processes which came later (in the 50s), and they will never fade. However, because a single print requires 3 separate negatives, other problems arose over time. Each of the negatives, made of plastic celluloid, began to shrink and crack, and of course, each would shrink and crack differently from the others. When re-printed, registration of the 3 colors becomes a problem — magenta and yellow “halos” around objects could be seen, from mis-registration.
Enter computers and the 21st Century. Warner Brothers has patented a digital technology called “Ultra-Resolution” which basically involved scanning in each negative separately, digitally correcting shrinkage, and re-compositing the files digitally, and then outputting onto DVD (or whatever digital file).
So far, only 4 films have benefitted from this, the first being Singin’ in the Rain (1952), and the others The Adventures of Robin Hood (1937), Meet Me In St. Louis (1944), and the piece de resistance Gone With The Wind (1939). The first three were done with a resolution of 2K, meaning 2000 vertical lines, plenty for high-definition digital presentation, and not quite up to the 35mm original film quality. But the latter was done at 4K, a far better resolution, and it will probably be re-output to negative celluloid. Currently in Ultra-Resolution production, The Wizard of Oz (1939).
I recommend all these films highly, not least because of their splendid and eternal worlds of ravishing color.