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Post by Simon Smith on Oct 31, 2010 14:48:36 GMT
I was just curious as to what the lifespan of 60's recordings was. If, in theory, an old 60's VT or kinescope had been living in a box in an unused room for 45 years and it was discovered today, would it still be decent quality? No, I haven't got a lead on anything, I was just wondering...
Thanks
Simon
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Post by Tim Disney on Oct 31, 2010 19:24:06 GMT
The big factor for both of these formats would be temperature and humidity, followed by the manufacturer of the tape or film stock. In normal room temperatures and low humidity, these formats could quite easily survive to this day. The biggest problem in the case of the tape is that the hardware to play it back and the accompanying engineer capable of getting a good transfer from it are proving to have a much lower survival rate.
Poor quality tape stock could result in an unstable and decomposing base, which means the magnetic oxide is liable to crumble away on playback. Poor quality film stock will suffer from 'vinegar syndrome' which is another form of chemical decomposition. The film shrinks and warps, eventually becoming unplayable without specialist telecine equipment, and in extreme cases, the emulsion and picture information comes away and disintegrates.
In theory, both would be perfectly playable if they've been kept in a typical room as part of an inhabited property. Attics and sheds are bad, bad, bad!
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RWels
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Post by RWels on Nov 1, 2010 13:29:52 GMT
There are even some tapes that need to be heated in an oven before they can be played again. But I don't know the exact story (perhaps someone can give more information about the how and why).
Almost anything can be played back again and transferred to a modern format (including tapes from 405 line systems such as the sony CV2000).
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Post by brianfretwell on Nov 2, 2010 12:23:51 GMT
There are even some tapes that need to be heated in an oven before they can be played again. But I don't know the exact story (perhaps someone can give more information about the how and why). Almost anything can be played back again and transferred to a modern format (including tapes from 405 line systems such as the sony CV2000). The story of and reason for baking is explained in the "Peladon Tales" article on the DR Who Restoration Team website. Basically it helps by reducing the moisture content to prevent oxide shedding and this prevents head clogging on the playback VTR. |
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RWels
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Post by RWels on Nov 2, 2010 21:41:41 GMT
Basically it helps by reducing the moisture content to prevent oxide shedding and this prevents head clogging on the playback VTR. Oh yeah, I recall some story about a tape that could only be played three minutes at a time before the head was full of oxide(or other stuff). Play three minutes, clean head, play next three minutes... I forgot which show it was but it must have been a time consuming recovery.  |
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Post by Robert Belford on Nov 3, 2010 14:19:52 GMT
Standard tape is reckoned to have a life of about 50 years. But it depends on how it was manufactured and how it has been stored. For example regular changes in temperature are bad because tape is a layer of backing, binder and oxide coating - all of which respond differently to changes in temperature: expanding and contracting. Suffice to say many tapes will still be around in good condition when there is no equipment left to play them on.
Also in the 1980's(?) metal-based tapes were introduced and at the time Sony would only commit to those having an expected lifespan of 15 years. I'm not clear which pro formats used that formulation but Video8 and Hi8 certainly did.
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RWels
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Post by RWels on Nov 3, 2010 17:10:32 GMT
Suffice to say many tapes will still be around in good condition when there is no equipment left to play them on. Well I am not so sure about that. Difficult, yes, but not impossible. Are there really tapes for which there is NO playback equipment anywhere in the world? However the chances for lost television to turn up are getting smaller. For the movies too. Metropolis was found, but what are the odds for something like the famous (and famously missing) Cleopatra from 1917 to turn up? If there was a copy somewhere it probably decomposed years ago. |
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Post by Ewan Montague on Nov 3, 2010 17:17:06 GMT
re magnetic tape
at the risk of repeating posts above I'll get this out of my head as it comes, I will repeat info so please don't be offended I have read the posts but this is info I have
the peladon info will explain everything but just to add my piece, I know of magnetic audio tape that is about 50 years old and still plays fine, as was said above it all about temperature & humidity and stability of those factors as long as the neither humidity and temperature are within the best range for the medium and they change as little as possible then tape can last for quite a while
there are other factors such a mould in the air or infection of mould from infected tapes. There is also the effect of magnetic radiation which varies from location to location both natural and industrial.
also the medium onto which the tape is stuck,ie the type of plastic or in some early types, paper. and further to that the type of glue or cement used to stick the oxide to the plastic. also the type of oxide used usually iron or Chromium.
this can get quite involved so I'll stop there.
I know I have repeated info but that's just the way my brain works.
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Post by Robert Belford on Nov 3, 2010 19:15:09 GMT
Probably there is equipment to play most things right now. Actually I wonder if maybe the 2 inch quad machines are easier to maintain than the more recent broadcast video-recorders? Are there really tapes for which there is NO playback equipment anywhere in the world? However the chances for lost television to turn up are getting smaller. For the movies too. Metropolis was found, but what are the odds for something like the famous (and famously missing) Cleopatra from 1917 to turn up? If there was a copy somewhere it probably decomposed years ago. |
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Post by markboulton on Nov 3, 2010 21:41:39 GMT
Actually I wonder if maybe the 2 inch quad machines are easier to maintain than the more recent broadcast video-recorders? No no no no no no no! Most definitely not!!!!!!! ;D |
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Post by Robert Belford on Nov 3, 2010 23:05:38 GMT
I thought due to the bits being much bigger. It would be possible to open them up and get an idea what's wrong  Do they have valves? Actually I wonder if maybe the 2 inch quad machines are easier to maintain than the more recent broadcast video-recorders? No no no no no no no! Most definitely not!!!!!!! ;D |
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Post by Steven Sigel on Nov 3, 2010 23:09:28 GMT
film and videotape are very different animals.
Acetate film that was processed properly and stored properly can last for hundreds of years. Mylar film can last literally almost forever.
I've got film prints in my collection that were struck in the 1930s and are just fine.
BTW - films from 1917 would be on Nitrate stock with is a different sort of animal altogether, although again, if stored properly it can last a very long time.
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Post by Robert Belford on Nov 3, 2010 23:21:50 GMT
In 1981 I was given a small roll of wartime nitrate film by a cinema projectionist. It was fine but within a year had turned to a syrupy goo and at that point would have been emitting highly flammable gas! I would guess it deteriorated due to the change in storage atmosphere? The Mitchell and Kenyon films which were found a few years ago were in great condition after 100 years. film and videotape are very different animals. Acetate film that was processed properly and stored properly can last for hundreds of years. Mylar film can last literally almost forever. I've got film prints in my collection that were struck in the 1930s and are just fine. BTW - films from 1917 would be on Nitrate stock with is a different sort of animal altogether, although again, if stored properly it can last a very long time. |
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