The term Digital Intermediate (DI) is one of the most frequently used in production and post discussions at trade shows and industry events. It is a term typically used in the feature film industry to describe the process of transferring film to data for all postproduction including color correction to create a digital master, which is used to create film prints, as well as digital deliverables such as DVD.
The process is involving an increasing amount of commercialmakers in feature production. Notably, Company 3’s Stefan Sonnenfeld served as DI colorist on such recent releases as Mission Impossible 3 and X-Men: The Last Stand. In the context of spotmaking, the DI process is typically used to enable “nonlinear” color correction or to create high resolution masters.
With rapidly developing technology including digital cameras and color correction systems, the tools and process are constantly evolving. So this is a good time to review the process and some of these concepts and terms.
Typical DI-style environments are data-based environments where frames are files.
There are three main qualities of an image: the number of horizontal lines of resolution, which is measured by “pixels” in the data world; vertical lines of resolution (also “pixels”); and bit depth (the number of bits representing the value of each pixel).
In today’s world of standard definition video, NTSC video is displayed at 640 X 480 lines of resolution; in high definition, the most commonly used format is 1920 X 1080 lines.
Some industry leaders believe that when data production gets off the ground, commercials will be produced at a higher resolution in “2k” data, or 2,048 X 1,556 lines. This is the resolution commonly used today on features for DI work.
The most commonly used 2k data has a 10-bit depth; this combination amounts to storage requirements of 12 megabytes per frame. That is a staggering number, keeping in mind that a 12 megabyte text file equates to the size of a document with more than 600 pages.
Some believe the standard could go higher than 2k. In the feature world, some facilities are beginning to reach for 4k–4,096 X 3,112 lines–or four times the picture information in a 2k file.
To that end, earlier this week, Sony unveiled the next generation of its SXRD 4k digital cinema projector–an 18K Lumen prototype designed to enable the theatrical display of 4k imagery. More than 1,000 members of the community packed Hollywood’s Digital Cinema Lab on Monday night for the preview, which included a screening of the 4k-mastered The Da Vinci Code, as well as four 2k trailers. Sony suggests that its next generation would be ready at the end of the year.
SHOOT senior editor, technology and postproduction, Carolyn Giardina can be reached at 310-822-0211 or at cgiardina@shootonline.com.
