Kodak Brings Digital Art to Film

by Bruce N. Goren

I'll own up to some bias first, though I've spent the past 13 years working in television technology - my first love is film. In fact I did a semester of post-graduate work at the University of Iowa on a Kodak sponsored Visual Scholar fellowship. Some video techs are cynical in the presence of film people waxing poetic about their medium, kinda like pre-pubescents snickering at make-out scenes. Non-linear video edit systems look more and more like the film bins of my college days. It takes me back to the warm feeling of holding those transparent necklaces of sequential imagery in my cotton-gloved hands.

You might have expected this column to begin with some cliche hype line such as " I have seen the future of the motion picture industry, the future is DIGITAL" . Well, not so fast TV Technology fans, not so fast. In spite of the promise of various competing HDTV proposals , 35mm film as the ultimate mastering medium is here to stay. New stocks are continuing to push the envelope of contrast range and sensitivity, while the physical resolution of the fastest formulations is almost unmeasurable. Add to that the ability to crank a camera beyond the standard 24 FPS and you have a bandwidth that high resolution video systems will be hard pressed to approach for the foreseeable future.

Film remains the highest resolution, and longest lived archival media available that can be played back with universal compatibility for eventually high fidelity transfer to any present day or future video distribution format.

Kodak says the future of film is CHEMICAL - emulsion for camera original, emulsion for theatrical release. What goes on in between though, what is known as the intermediate stage, is gonna be one wild computer generated digital ride.

Ed Jones is the President of Cinesite, Inc., which is a wholly owned subsidiary of an Eastman Kodak Company. Jones started in the film industry as a lab technician at Industrial Light and Magic. Over the course of a thirteen year career with ILM Jones rose through various positions from Creative to Senior Executive. Says Jones " Until recently, we have been "dating" technology. Now we are married to it. There is an on-going blending of computer, video, and film tools, and a subsequent explosion of technology."

Don Miskowich, Vice President - Sales and Marketing for Cinesite, gave me an in depth look at the technology behind the Kodak Cineon Digital Film System, formerly known as Kodak's electronic intermediate system. The Cinesite Digital Film Center, tucked away on the second floor of a bank building in Burbank, was opened for Beta-Site test basis business at the end of September. Because of the uncertainties of release dates and respect for client secrets, it's not possible to say which upcoming motion picture will be the first to exhibit with Cineon composited effects work. There should be a slew of them coming out this summer though, and Miskowich did allow that "Super Mario Brothers" (effects by LightMotive) would be among the first. (In fact, as we walked through a session in progress, I noted a frame up on a monitor that seemed to be from that film.)

Videographics artists and pre-print image processing veterans will find the basic idea of digital intermediate familiar. In the video graphics suite a Harry operator might digitize camera original video frames for rotoscope paint and touch-up for eventual layback to the edit master. A Mac maven would use a flatbed, or drum scanner to input a photo for cropping, filtering, or special effects image processing with PhotoShop or Aldus Gallery effects and later make separation films for printing. These are relatively small chunks of data that can be handled by high end PC's and mid-range workstations or proprietary processors. Kodak Cineon brings this same toolset of scanning, digital image manipulation, and transparently re-recording back to the original media format, to the realm of motion picture filmaking.

Why bother ? For the same reasons that video special effects work has evolved from the analog to the digital domain. Like analog video, optical film effects work, scene salvage work (removing wires, telephone poles, jet contrails etc.) , matte layering, re-framing, and scene transitions, besides being very time consuming, tends to result in a build up of noise, artifacts and the general detail degradation attendant to generational loss in analog media. Film effects rendering turn around time is also very frustrating to anyone who has ever worked in video or computer graphics. The idea was to bring to film optical effects work the interactivity, and transparent generations freedom available to video producers in a state of the art D-1 suite. The difference being of course that inputting the master and outputting the final product are not real-time operations. Scanning from and printing back to film at camera negative quality takes about 3 seconds per frame. Anyone who has ever suffered through scanning in a photo for a PC on a flatbed, or outputting a picture file to a 35mm digital film recorder realizes that Cineon has scored an engineering breakthrough to be scanning and writing at these resolutions and speeds.

The engineers at Kodak , in an effort reminiscent of a NASA project, had to re-invent every component of the system over the short course of a two year development period. In order to capture and preserve digitally as much of the camera negatives' quality as economically feasible while not exceeding available computing technology's ability to manipulate images in near real time for user interactivity, new design specifications were defined that go way beyond anything found in HDTV or computer graphics work. Off the shelf scanners, data recorders, computer workstations , software, and film recorders, even video monitors, simply could not meet the demanding specifications of film flatness, noise threshold, storage medium capacity, processing power, data transfer rate, and color stability required by Kodak scientists to keep the digital intermediate transparent and the system interactive. By transparent Kodak is talking about not being able to detect a qualitative difference between original camera negative scanned in, and the dupe negative printed out.

The pin registered scanner must move film past the three linear CCD arrays with extreme precision. Conventional camera and telecine gates and movements would not insure stability and perfect flatness at these resolutions. To insure film flatness, Kodak engineers found they had to wrap the film around a drum in both the scanner and laser beam printer, and then rotate the entire pin and drum assembly past the CCD array or laser beam printer guns. The R,G,B, filters for the CCD arrays had be formulated to precisely match the characteristics of motion picture film stock. In order to compensate for minute smearing during sampling due to media travel, image processing routines similar to the edge detection and detail enhancement circuitry of video CCU's had to be developed. Exotic lens and mirror technology had to be pioneered to control the scanning mechanics and dot geometry of the digital optical printer. Inventions were solicited via Kodak's corporate E-mail system and serendipitous solutions came in from the far reaches of its' multi-disciplined R&D efforts.

The amount of data this system handles is enormous. By way of comparison, a typical frame of video digitized to 32 bit R,G,B takes up less than a megabyte of storage medium. I could put a frame of video on a floppy, (two or three using D-2 or D-1 specs) but at thirty frames per second, the megabytes add up fast. Pre-press still images at 4-K resolution and truecolor bit depth typically run around 36 megabytes, and comfortably fit, one image per cartridge, onto a syquest 44 meg removable drive. The Cineon tri-linear pin-registered 3 X 4096 one pass scanner generates files of 30 to 40 megabytes per frame of 35mm 4 perf film ( Academy 2664 x 3656, Cinemascope 3112 X 3656, Super 35 3112 X 4096 ) and over 75 megabytes scanning from 35mm 8 perf (VistaVision 6144 X 4096). These various pixel dimension measurements represent an equal scanned resolution in actual digital samples (167 pixels) per millimeter regardless of film format. If you plan on releasing to HDTV or NTSC and don't mind not having the data necessary for 35mm print mastering you can save money by scanning at half or quarter resolution. Theme park ride footage and other specialty applications shot in 65mm need to be duped over to VistaVision format since the system only handles 35mm film stock.

These are not the 8 bit per color channel files we are used to working with in video . The typical 256 levels of video R,G,B exceeds the human capacity to perceive differences in adjacent, differently colored pixels. Kodak engineers felt they needed 1000 levels, or 10 bits per color channel per pixel to accommodate films greater contrast range and satisfy the requirements for clean matte separations used in compositing work. The linear luminance values are actually measured by the scanner at 14 bits. Scan data is stored in printing density format to better represent the light transmission characteristics of film. The added bonus is that these logarithmic numbers require only 10 bits for representation . This extra headroom promises to revolutionize color correction and motion picture blue-screen work , allowing for quicker, less critical lighting setups. Kodak Cineon has licensed the equations for its computer generated matte work from Ultimatte. In fact, the user interface software completely duplicates with on-screen slider bars, all eighty or so tweakable parameters of the rack mounted Ultimatte-6 hardware.

Just as on a PC-based pre-press system, the Cineon workstation is in a sense an off-line session. You are working at a screen resolution somewhat lower than the data file itself. The Cineon canvas screen uses a 1280 x 1024 computer monitor that has been color corrected to accurately represent film . It is only by virtue of being able to operate on less screen data that any kind of interactivity is possible when painting and matting such huge digital images. Like with making an EDL off line, an instruction log is then applied to the full resolution files for on line image processing, which can later be re-tweaked in this lower resolution interactive mode, or sent on to the laser beam film recorder for output . Originally envisioned as a three strip infra-red laser recorder, recent advances in technology prompted a switch to a more elegant design utilizing three visible gas lasers. Using the same drum wrap for flatness and pin registered movement as the scanner, the three primaries are built up by blue argon, green helium, and red helium lasers using precision motors and exotic optics for film transport , beam deflection and spot geometry.

The Kodak vision of a working Cineon suite is a bit more genteel than most edit bays. The client has his own set of system and canvas monitors, set back and away from the operator. Will this result in fewer Maalox moments ?

Kodak is using a file format that is based on a future standard (??) that is a SMPTE Ad Hoc Group on Digital Pictures work in progress . The Cineon picture data file is a derivative of the TIFF (Tagged Image File Format) files typically used in computer graphics print workstations. Once the new format is formally defined it is anticipated that most major computer/video graphics manufacturers will incorporate bi-directional picture file translation into their software packages to accommodate image interchange ability . Miskowich envisions high end 3-D animation systems (typically 24 or 32 bit Targa format) sending matte element output to Cinesite for compositing, or importing Cineon scans into computer graphic scenes requiring rotoscoped texture maps. During my tour I noted some work being performed with rotoscoped Wavefront images. This non-proprietary attitude about the file format for Cineon's images is in keeping with an evolving computer industry philosophy that stresses an open systems approach to best serve users with a mix of installed hardware. For now customers with an immediate need are provided the specs on Cineon's image data protocol so they can translate their own computer pictures into Cineon compatible image files for use on digital optical projects taking place at the Burbank Beta installation.

The pre-production model of Cineon currently on-line at Cinesite is built around a workstation boasting 120 INMOS transputers arranged in a ring architecture. The parallel CPUs share a bulging 400 Megabytes of RAM and a 60 Gigabyte hard drive array for on-line picture data managed by a SUN host. High speed data recorders for archival storage, are expected to be able to accept data at up to SCSI-2's maximum transfer rate of 15 Megabytes per second.

In the future, it is anticipated that entire stock footage libraries could be maintained using these data cartridges and high speed recorders. At COMDEX last year, AMPEX showed a device called the TERASTOR. Basically a broadcast digital cart machine with data recorders in place of videotape machines, a device such as this with a library database,and robotics for retrieval, could be the cornerstone of a digital clip company.

Further along on my tour of Cinesite's machine rooms I spotted a pair of SGI Crimsons being used for off-line image paint and touch-up sessions. A second pre-production Cineon will go on-line in early 1993. Engineering model number three, with many modifications and improvements growing out of the lessons learned by early Beta site clients should be on-line at Cinesite shortly thereafter.

Kodak excepts to be ready to begin manufacturing and selling it's million dollar Cineon workstation sometime mid to late 1993. The production version software will implement final tweaks indicated by Cineon prototype number two. The hardware configuration will harness the power of the soon to be released Silicon Graphics power series computers using SMP (symmetric multiprocessing) technology and the RealityEngine (TM) graphics accelerator. These R4000 based machines will replace the transputer arrays currently running the Cineon prototypes resulting in major cost savings and upgradability. Customers will also have access to the more than 1300 software application titles featuring video editing, 3D animation, and image processing available from 3rd party vendors for the SGI family of computers.