RE: [AV Media Matters] Video to film for preservation-another perspective.

[e.ha.zwaneveld@nfb.ca]

Greetings,

tcorlis@yahoo.com [mailto:tcorlis@yahoo.com]

Asked:
I have a question that may be coming from a strange direction, but I keep
coming back to it.  What is the feasibility and potential economic
consideration for using motion picture film as a preservation medium for
things that are currently recorded on video?  I ask this because it seems we
have a better handle on preserving film over longer terms, and I wondered if
anyone had experimented with this idea.

Reply:
One of the more recent digital techniques for transferring video to film
using digital signal processing, has been applied for television
commercials, especially in Europe, for years. The results vary, depending on
the computing power and enhancements applied.

Using Teledyne Electron Beam Recorder equipment, major Hollywood motion
picture laboratories, such as Consolidated Film Industries and the National
Film Board of Canada in Montreal, have transferred countless hours of 2-inch
Quad and 1-inch type C video to 35mm and 16mm film since the 1970's with
results good enough to make the higher cost worth it.

More advanced techniques have been used by companies such as Image Transform
in Universal City, California, also starting in the 1970s. Their video to
film transfer results were even better. They used sequential three-color
step printing to a 35mm black and white panchromatic separation film, which
was subsequently transferred to a 35mm color intermediate film. Having been
purchased by Four Media company (4MC) in Burbank, Ca, the Transform Process
service remains essentially unchanged, using an electron beam recorder and a
sophisticated color imaging system. Video pictures are transferred from all
current broadcast standards to 16mm or 35mm film. This approach works well,
because "the equivalent "bandwidth" of 35mm film is in the general area of
35MHz, which is about six times the resolution of most broadcast video
systems." (From: 4MC-Transform Services-Shooting Videotape for Transfer to
Film, page 4.) Many other major video post facilities provide film to video
transfer services. This was and is not confined to Hollywood though.

In the 1980s, the NTSC-based Gemini system was used to produce soft focus
backgrounds, inserted in digital form into film sequences. Video used in
films was and remains acceptable as a technique for certain music videos and
tv commercials, to be shown on the television screen. At the National Film
Board of Canada we also have successfully used NTSC sequences of news items
in our documentary films, where the loss of sharpness as compared with the
film source material was acceptable because of the newsreel nature of the
shots we inserted.

To evaluate the picture quality of the HDTV system as compared with 35mm and
super 16mm film in the 1980s, we were interested in using the then Telesat
owned mobile HDTV production facility, equipped with digital HDTV VTRs. But
we found the 50% discounted cost of renting the HDTV camera at CDN $ 10,000
a little too steep. So we used a different approach. Two of our leading
cinematographers produced two eight minute sequences with critical content,
using widescreen 16mm (Super 16mm) blown up in our laboratories to 35mm film
negative. Simultaneously, they shot the same sequence in 35mm color
negative. This enabled a comparison between 35mm and 16mm film, transferred
on a HDTV telecine to Hi-Vision 1125/60 analog video. (The transfer from our
S16mm and 35mm film source materials by this HDTV telecine cost CDN $ 500 a
minute). Then the resulting HDTV videotape was transferred back again to
film on the Sony PCL Electron Beam Recorder (EBR). This unit placed
successive black and white frames, through Red, Green and Blue separation
filters, onto a 35mm Vistavision format black and white panchromatic film.
(The cost of transferring the HDTV recording cost CDN $ 1,000 a minute, plus
shipping and/or traveling expenses to Tokyo).  We demonstrated the results
at a HDTV Colloquium in Ottawa, Ontario. The film to HDTV and back to 35mm
film work was done by Sony PCL in Tokyo, Japan.

It demonstrated that shooting film at 24 frames per second, transferring it
to 30 fps video and back to 24 fps film would cause a frame mismatch that
made intercutting those materials impossible if content accuracy mattered.
We also noted that we picked up a color fringe around moving objects, we
obviously got a partial picture which did not belong where we saw it. It
showed that interlaced 30fps Hi-vision HDTV video (and NTSC video for that
matter) were not particularly appropriate to deliver a good film image, if
used at the intermediate stage. The test series also included a color
positive print that also went through the HDTV path and back to film again.
For the same frame rate incompatibility reasons explained above, it showed
color strobing, which was far more disturbing than the quality we saw from
our negatives.

What is particularly relevant to this discussion, our negative film source
materials actually lost visibly some sharpness, most noticeable in long
shots or distant and smaller objects in a scene by passing them through the
HDTV step. If film and video frame rates were to match, and the image was
not interlaced but progressively scanned a match could be obtained, albeit
at some loss of sharpness. We knew that if we had done the test using NTSC
or PAL video, we would have lost even more sharpness. We were not to use
this approach for visual effects, because of the next development.

The Los Angeles area based Technology Council of the Motion
Picture-Television Industry, of which I am one of the founding members,
under the chairmanship of Richard J. Stumpf of Universal Studios, completed
a study of the "Requirements of a Digital Film Master". It invited industry
comment and was well received. At the 1989 UNIATEC Conference in Montreal,
the National Film Board of Canada proposed the ULTimate Image Processing
System (ULTIPS), "to provide fully electronic, fully digital post-production
of film. Film would be used as the input medium and could be used as one of
the output media, with all intermediate processing performed on digital data
representing images and sound." We envisioned "a system that would have a
frame rate of 24 Herz(same as film), Interlace 1:1; Scan lines/frame: 1836;
Scan rate: 44.064 Kiloherz; and a bandwidth of 162.7 Megaherz. The
progressive scan would allow an iintelligent monitor with a frame store to
convcert this to a 48- or possibly 72-Herz display so as to eliminate
flicker, without introducing unacceptable motion artifacts." (Frederick
Gasoi, Ed Zwaneveld, ULTIPS-The ULTimate Image Processing System", in
UNIATEC Proceedings, pp. 288-311).

Not long after this, Eastman Kodak introduced its Kodak High Resolution
Electronic Intermediate System, (DeMarsh, Hunt, Kennel $ Kristy, in October
1989, "to provide the entertainment industry with a digial means of
combining picture film images, essentially creating a digital version of the
optical printer. The system would scan and digitize film images so that they
could be interactively manipulated and composited at a computer workstation
and then recorded back to film." (Eastman Kodak Company,"Kodak High
Resolution Electronic Intermediate System", April 1991). The use of digital
processing of film images and subsequently producing a film intermediate
using a film recorder was born. This was not digital video but digital data
tape recording of film images, and using it to go back again to film.

So the technology was now available not only to capture video images as
data, but also film images, and after manipulating them and enhancing them,
recording them back to film, or video or both.

Meanwhile, Sony has brought its progressive advancements in HDTV technology
to Hollywood and London, where their 1125/60 Hi-Vision HDTV technology was
applied to restore old motion pictures and to create new film masters, as
well as masters suitable for DVD replication. They were soon also using
digital techniques to capture and enhance film images.