Video Tapes Don't Last Very Long... Rubbish!
Tuesday 26 November 2019
The accepted wisdom for many years has been that video tapes are not good long-term storage formats for your precious AV material. There is sense in the theory, but in practice, things are quite different.
The video signal is recorded to the tape as a very weak magnetic signal of almost imperceptible strength and the 'theory' has always been that this fragile signal degrades over time. Other environmental factors - mostly temperature and humidity, will cause other problems.
Recently, a friend asked me to create an MP4 clip from a VHS tape that was recorded in 1980. Since then, it had been stored in a cardboard box, with many other tapes, in a loft - probably the absolute worst domestic location in which to store a video tape - year-round extremes of temperature - dusty at times, humid at others.
So having established that there was no physical damage to the cassette, it was with a sense of trepidation that I put it in my VHS player. I warned my friend that we may end up dismantling my machine in order to recover the remnants of his tape from its deepest, darkest corners. I decided to "go-for-it" with the digitisation process, without previewing it, incase this was the only chance we had to play this 39 year old archive... lo and behold, it played perfectly - no tracking issues, no dropouts, no head-clog, no skittish audio and absolutely no wrapping itself around the mechanism of my player. So - the 'theory' couldn't have been more wrong. Let me explain why, in 'practice' a video tape is actually a very good long-term storage medium and what the real long-term problem is.
As I said at the start, on a video tape, a very weak magnetic signal is recorded onto a very thin, fragile tape covered in what amounts to rust - yes, iron-oxide dust particles. Iron is very magnetic and therefore the best medium to record a weak signal to. On it's own, any exposed short section of that tape could easily have the signal affected by outside influences. But in practice the tape is stored in a plastic cassette and at any point of play, almost all of the tape is wrapped in a tight 'pancake' either entirely on 1 of the spools (start or end of the tape) or divided across both spools. So the fragile signal is actually very well protected from these outside influences pretty much all of the time.
There is a phenomenon called 'print-through' where 2 magnetic signals in close proximity can affect each other. But tape manufacturers became very good at formulating the chemistry of their tapes to avoid this problem. A large, packed spool will be slower to react to the temperature changes. Dust particles will not come into contact with the signal surface since it spends very little time exposed. A magnetic signal IS affected by temperature variations, but it actually needs a much greater variation than most households (and lofts) will ever experience. Given that most household tape collections are probably stored in the same living conditions as the human occupants, the life of a stored video tape is actually quite gentle and luxurious.
So what storage conditions WILL adversely affect a video tape? Well, other magnetism will do most damage, but again, the magnetic forces found in the average home are unlikely to wipe a tape on first contact. Loudspeakers, old CRT TV's and microwave ovens all have powerful magnets inside them, so storing tapes on or quite near them is not advised. Repeated damp/dry cycles from being in a moist environment which then dries out can cause fungus and mildew to develop, but this is usually on the outside of the pancake. It can be removed gently by a soft brush before playing the tape (if you know how to dismantle and rebuild a cassette safely). In my friends case, the cardboard box that he kept his tapes in probably also helped to absorb moisture from the air over all those years.
Physical mis-handling of tapes does most of the damage, dropping them being the worst offender. Putting them in their cases the wrong way round forces you to pull them out of the case by the flap, either breaking it, or causing you to touch the exposed signal surface
So if I think video tapes are, in reality, good long-term storage options, why do people in my line of work keep telling people like you to get their tapes archived as soon as possible?
Simple - the weak point in the world of videotape is the machines to play them on. As the machines get older, they wear out and break down. Replacement parts are increasingly hard to get, and if you can get parts, who is going to fit them? - even in the 70's, the technology inside a VCR was a complex thing requiring special skills and equipment to work on. Ebay may be awash with VHS players, but you take a gamble on their condition. Try getting hold of Betamax, U-matic or 8mm players in good working condition.
Here at Oxford Tape Studio, I use what would generally be classed as pro-grade machinery. These machines are better built than those intended for the domestic market so they tend to be more robust, more reliable, and have greater options on settings.
So if you have any old tapes stored around the home or at work, consider whether or not the material on them could be of true value, historically, professionally or just emotionally. Don't keep staring at them thinking 'one day...' make that day today and give me a call to talk about what we can do to bring that valuable video material into the modern age before the hardware disappears and you are left staring at perfectly good, but unplayable video cassettes.