A D.I. Primer

by M. David Mullen, ASC

A “digital intermediate” has become the trendy must-have thing for filmmakers, so much so that they toss around term loosely, trying to sound hip and cutting-edge, making it almost useless as a description of a post-production technique.

What a Digital Intermediate Is

“Digital” being a vague catch-all these days, the clue as to the meaning of the term lies in the second word more than the first: “intermediate”.

The Traditional Photochemical Route

In traditional photochemical post-production, an intermediate is a duplication element (a.k.a. “dupe”) needed to protect the original camera negative from being damaged by over-printing. While shooting, the processed negative is usually transferred to standard-definition video for dailies and offline editing. The final EDL is used by the negative cutter as a guide to conforming the camera rolls to the video edit, cement-splicing the various pieces of negative together. The cut negative is then answer-printed to determine the red, green, and blue printer lights needed to balance the colors and density (brightness) of the image on the print. Using these same printer light numbers, a color-timed positive copy is also made of the negative onto a low-contrast intermediate dupe stock. This is called the interpositive (I.P.); this is then copied onto the same stock to create an internegative (I.N.) from which prints can be made. The I.P. serves as a protection master when archiving the film, plus will be used for the final transfer to video since it is basically a color-corrected copy of your original negative without physical splices. Since the I.N. is on a stronger polyester base, compared to the acetate base of the original negative, you can literally strike hundreds of prints off of it, if not a thousand, before it wears out – and when it does, you just strike another I.N. off of the I.P.