Film-Tech Forum ARCHIVE: How were/are video transfers made?

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Posted by Aaron Garman (Member # 1653) on 07-29-2011, 09:48 PM:

So I think I understand modern transfers: there is a master digital file that is then compressed for Blu-ray/DVD/etc. and then loaded onto the disc in the respective file format. That master digital file of course comes from many a different source, but I'd guess many from a 2K workflow.

My real question is how did it work before digital editing, digital tape, etc? How did they get the film (whether from a OCN, release print, etc.) onto say VHS, LaserDisc, or even television? And what format were those master tapes in? I'd imagine even some early DVDs had some sort of master tape before all digital workflows became popular.

Sorry for the novice questions, but I'm trying to understand that despite formats like Blu-ray having so much better resolution and clarity, that some of my old LaserDiscs have a more natural, analog, film-like look despite lower resolution and video noise.

AJG

Posted by Mitchell Dvoskin (Member # 751) on 07-29-2011, 11:11 PM:

While I am sure that others can answer in more detail, basically files were transferred to tape on a Rank or similar analog device, which doubled some frames during transfer to accomplish the 24fps to 30fps conversion. In advance of the analog transfer, the technician would program the Rank by running slowly though the film, adjusting the color/brightness/contrast for every scene as needed. If it was a pan & scan transfer, they would also program the Rank as too what part of the wider film picture was to be transferred. When they completed the programming of the transfer, they would run the film while the controller implemented the program.

Various different tape formats were used over the years. I know that the early LaserDiscs were mastered from 2" quad videotape, a high quality non helical scan tape format that was obsolete by the early 1980's.

Posted by Scott Norwood (Member # 30) on 07-30-2011, 07:54 AM:

The earliest system (used from the beginning of television through the 1980s and, to some extent, still) was a "film chain." This typically consisted of one or more 16mm or 35mm film projectors set up to project into a multiplexer (mirror device) that directed the images to a film-chain camera. The output of the camera would then be broadcast on the air or recorded to tape. 2" Quad and 1" C-type would have been common in the 1970s through the 1980s, with 1", Beta SP, D1, D2, and Digi-Beta becoming more common in the 1990s. D1, D2, and Digi-Beta are all digital formats; the others are analog.

Film-chain projectors in NTSC-land have fast-pulldown intermittents and 5-bladed shutters in order to sync properly with 59.94 Hz interlaced video. In PAL-land, the film is run at 25fps for the same reason.

Every TV station had a 16mm film-chain setup through the mid-1980s, at least. (Some may still have the equipment.)

I believe that flying-spot scanners like the Rank and Bosch were a 1970s and 1980s invention. Unlike film chain equipment, they are gentler on film and allow transfers from negative material, as well as scene-to-scene color correction. These are still used widely today, although frame-by-frame scanning has become more common, at least for big-budget feature films.

In 1995, I was involved with a project where the recommended process (which we followed) was a Rank film transfer to Beta SP, then a dub to 1" C-type for use as a master for low-volume VHS duplication (about 100 copies). Beta SP was considered to be of higher quality, but 1" was considered to be less prone to dropouts. The duplication process involved a playback deck, a distribution amp, and a rack of high-end VHS VCRs. High-volume VHS duplication is/was an entirely different process, which I don't know enough about to explain here.

Posted by Bobby Henderson (Member # 840) on 07-30-2011, 10:18 AM:

Today most movies shot on film go through the digital intermediate process and no longer use traditional telecine systems that dub the film image to analog or digital tape in real time. These days the image is digitally scanned and then processed with a variety of software tools.

Current film scanners don't have as many of the technical problems that are inherent to traditional telecine systems. Some use the term "datacine" for these types of systems. Film scanners either carefully scan each film frame one frame at a time or pull the film through in continouous motion. Either way the systems are built to hold the images in a far more steady, more tightly focused manner. The software systems can correct a variety of problems, including movement of the film image. Some of that image-steadying technology has found its way into more mainstream applications like Adobe After Effects (the new warp stabilizer feature). You get a far more precise, more dynamic looking video master with the current crop of film scanning and post production image processing tools.

Here's some links to PDFs about certain film scanners currently in use.

Spirit 4K PDF

Northlight PDF

ARRISCAN PDF

Posted by Aaron Garman (Member # 1653) on 07-30-2011, 11:25 AM:

Great information everyone, thanks a bunch.

AJG

Posted by Hillary Charles (Member # 769) on 07-30-2011, 01:12 PM:

quote: Scott Norwood
I believe that flying-spot scanners like the Rank and Bosch were a 1970s and 1980s invention.

Believe it or not, the flying spot scanner goes back to 1930s Germany!