Edit Points: A History of Videotape Editing

Video editing pioneers didn’t have the simple pleasures we take for granted today. As you may already
know, they didn’t have things like time code, computer-based editors or Video Toasters. But did you know
they also didn’t have electronic editing, audio dubbing or even slow and fast motion picture search?

The first editors worked with the equivalent of a chisel on stone to put their ideas together on tape. They
could only dream about many of the features now taken for granted by videomakers.

Looking back over the last 40 years of videotape editing, one familiar statement rings true–you’ve come
a long way, baby.

From Primitive Beginnings

2-inch quadruplex was the first videotape format, so named because of its two-inch wide tape and 4-part
record pattern. Ampex designed the format and built the first machine, the VR-1000, which used tape
created by the 3M Company. The two debuted in 1956.

The system Ampex designed to edit 2-inch tape was quite crude, so much so that calling it a system
might stretch the truth. They modeled it after the cut-and-splice editing done on motion picture film.

If you know the technical specs of today’s video formats, you know that physical splicing is basically
impossible. Our modern VCRs use helical scanning to record intricate patterns along a wide section of
tape. Simple cut-and-splice editing won’t dissect and reconstruct those patterns precisely enough to safely
play them back.

The 2-inch format, however, predated the helical formats. Its video head spun perpendicular to the tape,
recording nearly vertical video tracks. Although it required high precision, editors could connect scenes by
cutting and taping together the pieces for a finished edit. Until electronic editing appeared, that’s exactly
what they did.

Get Out Your Razor Blades

To improve both the editing process and the final tape, a company called Smith built the Smith-Editor, a
mechanical splicing station for the early videotape recorders. It included a microscope, of all things–the
idea was to find video fields below each control track pulse and cut between them so as not to disturb the
picture on playback.

A special bar on the editing block showed editors exactly where to cut the tape to preserve the control
track sync. Without such a device, you’d have a hard time making a splice edit. A random cut would badly
alter the control pulse pattern and make images jump, jitter and roll.

Along with the splicing block came a special solution loaded with alcohol and powdered iron shavings.
Editors applied this "developing solution" to the oxide of the tape where they wanted to make an edit.

As the alcohol dried, the bits of iron collected along each recorded video track. They left a series of
narrowly spaced lines on the tape. Editors used the microscope to make precise cuts in the tape along these

Finding the actual edit point on a piece of tape was a challenge. Unlike our VTRs, the first machines
couldn’t search the tape in slow or still motion. That meant editors couldn’t see images on a monitor to find
a precise edit point.

Can you imagine trying to find an edit point without seeing the image on the screen? That’s basically
what they did. They played the tape to a point near the edit point and stopped the machine. They wound the
reels by hand backward or forward to where they thought edit should happen.

Knowing how the tape moved through the machine helped them guess the right position, but it was
never a precise technique. They would make a splice only to find they either clipped a take short or left a
little "slop" at the end.

When they found the approximate edit location, they put that section of tape into the editing block. Then
they applied a strip of the developing solution to the tape they were about to cut.

Under the microscope, all they could see were narrow rows of iron particles. Using the small metal bar
as a reference, they lined up the visible tracks and cut the tape with a very sharp razor blade. They prepared
the second piece of tape essentially the same way.

The editor then flipped the two pieces over and applied a piece of mylar tape to the back. Presto: A
videotape edit.

No one knew for sure what would happen when a splice played back on the VTR. Sometimes the upper
portion of the screen jarred to one side for a few frames after the edit point. Other times, you’d see a brief
flash of snow. Once in a while, the splice came apart and the tape would stop playing.

On rare occasions, the splice would go by without disrupting the image at all–a perfect edit.

At its finest, the entire editing process depended on educated guesses and pure luck. George
Sollenberger, a video engineer who spent 38 years with the NBC affiliate in Denver, worked with one of
the Ampex’s first videotape machines. He says even the best editors couldn’t guarantee more than 50
percent accuracy when finding edit points and splicing them together.

Electronic Editing Arrives

Everyone who worked with the early videotape machines dreamed of a more precise way to arrange their
ideas on tape. Creative people wanted more control over the aesthetics of their work. Engineers wanted a
process that did less damage to tapes and machines.

Their dreams came true about the time that Ampex released the VR-2000, a color machine which could
perform edits electronically. Ampex labeled this editing technology the Editech system, and offered it as an
upgrade to all existing Quad machines. Although nothing like the insert editing we know today, it freed
video editors from the hassle of splicing tape.

The first electronic edit machines provided on-the-fly assemble editing. They could switch from
playback into record at the touch of a button, something their predecessors couldn’t do. They couldn’t,
however, record audio or video independently, something today’s insert editors do easily. They had no
time code, no way to mark edit points, and no preroll.

Just like the cut-and-splice technique, editors found edit points by stopping the tape near the start of a
scene and fine-tuning the reel position by hand.

With points marked on both machines, they manually wound the tapes backward an equal number of
control track pulses. Then they started both machines playing at the same time. At the edit point, they
punched record on the master machine.

Two things determined whether the edit hit at the right time: the speed of the machine’s record switch,
and the carefully-timed twitch of the editor’s finger.

If the editor hit the button early, or if the switch started recording a fraction of a second sooner than the
editor guessed, the previous scene on the master got clipped.

If the edit happened too late, the editor had to decide if it was bad enough to take a second time.
Repeating edits got tricky because the window to get it right grew narrower and narrower with each
attempt. If the second try triggered too soon, it botched the master. If it triggered too late, it meant yet
another try.

Typically, alert editors and reliable machines could get within a half-second of the intended edit point
using this technique.

Automated Edit Controllers

Despite the improvements, early electronic editing still kept video editors too close to the process and
too far from the finished program.

It wasn’t until small edit controllers appeared in the late 1960s that editors could more closely address
the art of assembling programs on videotape.

The first edit controllers automated most of the editing process. They marked edit points electronically,
prerolled the machines, and triggered the record circuit at the edit point. Some could even preview an edit
before recording it. They were accurate enough to get within a few frames of the intended edit point.

With the 2-inch machines, however, editors still couldn’t search for the right edit frame in still or slow
motion. Instead, they set edit points on-the-fly as the tape rolled.

The ability to scan footage at slow speeds came with a format called 3/4-inch U-matic, which debuted in
1970. Like many video formats, it got its name from the tape width, and from the shape formed by the tape
wrapped around the video head.

Once they could scan scenes frame by frame, editors could pick the right edit point much more
accurately. As tape transports in 3/4-inch machines improved, the controllers could get within one frame of
the edit point, and often hit it exactly. That gave editors even more creative precision.

Both 2-inch and 3/4-inch still lacked a good way to describe the location of scenes on the tape. To make
up for this, editors used time counters on the machines as a reference for marking edit points, but those
numbers didn’t actually mark anything on the tape.

The only way editors could keep track of their position on the tape was to rewind the tape to the
beginning and reset the counter. By doing so, they could refer to the location of scenes relative to the start
of the tape.

During edit sessions, they usually needed a bunch of different tapes to create a show. If they wanted to
find a certain scene on any given reel, they had to first rewind it to the start and reset the counter before
shuttling to the scene they wanted.

Time Code Editing

The solution to this tedious problem came from a technology called time code. First developed in 1967 by
a company called EECO, it was based on a system used by NASA to "time tag" telemetry tapes. Each
frame of video had the hour, minute and second recorded with it. Engineers could easily find specific
pieces of data by going through these numbers.

The EECO system gained acceptance as an industry standard. Soon other manufacturers began
introducing their own time code systems, none of which were compatible. Things became chaotic quickly,
and in 1969 the Society of Motion Picture and Television Engineers (SMPTE) stepped in to develop an
industry standard.

With time code, video editing gained remarkably higher efficiency and precision. Machines could
consistently find not just rough scenes but specific frames on any tape. Editors no longer had to "rewind
and reset" to locate footage, because machines recorded time code on the tape with each frame.

CBS Labs and Memorex, in a joint venture company called CMX Systems, designed an edit controller
that took video editing one notch higher. Their machine, the CMX-600, was the first computer-based video
edit controller.

The CMX-600 used computer disks instead of videotape to store the video signal and a light pen
console for editing choices and to review playbacks. No tape was recorded during the edit process but an
edit decision list was generated and used with computers to assemble the program later. The disks also
stored transition effects and time code numbers in case an editor needed to change the program in the

Sometimes, editors could only use these editing technologies by incorporating the new features into
older machines. Companies sold things like time code readers and generators as add-ons for machines built
as much as a decade earlier. While this method worked, it didn’t make the most of the new features.

In 1978, the SMPTE set standards for three one-inch helical tape formats known as type A, type B, and
type C. Type A was the original Ampex format, type B was the existing Bosch-Frenseh european standard,
but type C was a compromise between Ampex’s type A and a new Sony format called BVH. Things like
live slow-motion, high speed search at up to 60 times normal speed and multi-channel audio were standard
with one-inch videotape. It offered the highest-quality picture and sound recording with the highest level of
precision available at the time.

The combination of one-inch videotape recorders and CMX edit control technology became the
foundation of the professional post-production industry we know today.

Trickle-Down Technology

Throughout these pages, you may have noticed that the consumer gear you use today seems similar to
gear the pros used a few years ago. That’s no accident. As broadcast technology has grown and stabilized,
it’s slowly fallen into the hands of eager hobbyists, trainers and corporate communicators.

The VHS and BetaMax videocassettes that began the videomaking revolution over a decade ago came
from the design of the 3/4-inch cassette. The ideas behind the edit controllers we use today first appeared in
the broadcast industry in the 1970s. In fact, some of our more basic edit controllers are simply
updated versions of controllers the pros used less than a decade ago.

Does that mean if we wait a few more years, we’ll have the same tools and tricks the pros use today?
The answer is almost certainly yes.

New digital tape formats are becoming the standard in big production studios because they offer almost
no signal loss and amazing editing flexibility. Sweeping changes in computer-based nonlinear editing now
give you the power to complete an entire program without making even one videotape edit.

As these technologies stabilize in the professional world, count on similar versions appearing in the
prosumer market.

Until they do, however, you may get frustrated by the hoops today’s gear makes you jump through. If
you do, look back at past technology and think about how the early editors put scenes together. It may give
you more patience with today’s technology, and more respect for those who didn’t have its luxuries.

The Videomaker Editors are dedicated to bringing you the information you need to produce and share better video.

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