The Master Positive
An interpositive (or IP) is a crucial intermediate element in the traditional photochemical film duplication pipeline. After the original camera negative (OCN) has been edited, color-timed, and conformed, it is used to strike the interpositive. This is a full-color, positive image printed onto a special, low-contrast film stock. Unlike a ‘release print’ meant for theaters, an IP is not designed for projection. Instead, it is a master print of the highest possible quality, created in a meticulously controlled laboratory environment. Its sole purpose is to serve as the source from which internegatives (INs) are made, which in turn are used to create the final theatrical prints.
Creating an interpositive is the first step in protecting the priceless original negative. By generating a perfect positive copy, the OCN can be safely archived and is no longer needed for the rest of the mass-production process. All subsequent duplication work, including the creation of prints for international distribution or home video masters, is done from the IP or elements derived from it. This prevents the wear and tear that would inevitably destroy the original if it were used to make every copy. The interpositive is essentially the new ‘master’ from which the film’s lineage of copies will be generated.
Characteristics and Archival Importance
Interpositives are made on special film stocks that have a finer grain structure and a wider dynamic range than projection stocks, allowing them to capture all the nuance of the original negative. They are typically low in contrast to ensure that detail in the highlights and shadows is preserved through the next stage of duplication (creating the internegative). The quality of the IP is paramount; any flaw, piece of dirt, or color timing error present in the interpositive will be passed down to every subsequent copy made from it.
From an archival standpoint, the interpositive is often one of the best-preserved elements of a film. Because it was used less frequently than an internegative and was handled with extreme care, an IP can often be in better condition decades later than any of the surviving release prints or even the OCN itself. For film restoration projects, a well-preserved interpositive is an invaluable asset. It can be scanned at high resolution to create a digital master, serving as the primary source for a Blu-ray release or digital restoration, especially if the original camera negative has been lost, damaged, or has faded over time.