An interpositive, intermediate positive, IP or master positive is an orange-based motion picture film with a positive image made from the edited camera negative. The orange base provides special color characteristics that allow more accurate color reproduction than if the IP had a clear base, as in print films.
From a traditional photographic perspective, an interpositive is essentially a negative processed in a positive process.
Photographers that create photographic art by "contact printing"; i.e. Platinum, AZO, need to create interpositives to create large negatives. The final art work has the size of the contact negative produced. Interpositives are also the best means of archiving or copying old image libraries. Reversal B&W processing can also be achieved by various kits and published recipes.
The interpositive is made after the answer print has been approved. All lights and opticals from the answer print are repeated when striking the interpositive, and once the IP exists, the original negative can be vaulted.
The interpositive is printed with a wet gate, contact print that has been done in "liquid", and historically has had only one purpose, namely, to be the element that is used to make the internegative.
It is sometimes referred to as a "protection IP", which is a good term, since the only time the IP is touched is on the occasion of making the first or a replacement internegative. Since interpositives are used so rarely, they are usually the film element that is in the best condition of all the film elements.
Interpositives are usually element of choice for film-to-tape transfers for several reasons:
- They are usually in better physical condition than the other film elements. The original camera negative is often checkerboarded on several rolls or may be chemically unstable if stored improperly.
- They are very low-contrast and therefore help to preserve shadow detail.
- Scratches or dirt on the IP appear as black defects on the transfer, which are generally less objectionable than white defects, which would be the case if the camera negative or internegative were used.