2. Then using the mattes, all the separate elements are put together using an Optical Printer
The Optical Printer
The Optical Printing Composite Process:
- Traditional matting, for a long time, was compositing by printing elements of different film strips onto a final duplicate film stock using an optical printer. This technique, although requires great precision, gave exceptional results and possibilities
- Firstly the action is shot against a blue or green screen. A matching camera filter blocks out the background color allowing only the action to be captured in the film.
- A high contrast film is used to get a contrasting (mask) image. This image is reversed using another high contrast film.
- The 3 film sandwich is run through the optical printer-The fresh film at the bottom, followed by the traveling matte with the background covered, on the top is the negative of the live action. The resulting combined print is the live action with a plain, unexposed background.
- Then another 3 film sandwich-The exposed film, the opposite mask, the background to be composited.
- Finally we have the positive printed composite which can be converted to a dupe negative and combined with the rest of the film reel. The process gets more and more complicated as the parts to be composited increase.
Take a look at a complex optical printing shot done for Star wars by ILM :