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28 Jul 09 - 03:06 AM (#2688572) Subject: Digitising Analogue Recordings From: GUEST,Chris J Brady [I tried to append this to the thread: What to do with old FSGW concert tapes? - but the system wouldn't allow me to. Perhaps this topic is better as a new thread.] To introduce a fly into the ointment (or whatever) the major archives of historic magnetic media recordings seem to end up on CDs or DVDs in the - to my mind - mistaken belief that these are suitable for archiving. I am very leary that these optical media are reliable enough to be used for important archival purposes. Unfortunately many folk are tempted to buy a stack of disks of indeterminate (and unlabelled) quality. These can last for days to years - but ot forever. Sadly the black coated discs that Fuji and Kodak (?) used to produce are not now available. But whatever - this optical storage technology simply has not been around for long enough to test its reliability and longevity. With analogue recordings (like analogue t.v. in a poor reception area) at least you get something. With digitial once there is an error you lose the lot. Having said that Panasonic with its DVD-RAM discs do at least use error-correcting algorithms if a disc goes bad. Some of you might be aware of Tony Barrand's huge video archive of traditional dance. This is hosted by Boston University and is completely on hard drives. He has spent many hundred (thousadns) of hours conveting analogue video into digital and then uploading the results onto the professional hard drives hosted at BU. At least these are backed up during the normal administration of the database(s) so the archive is near permanent. The database is freely available to the public via the web site. But even the LoC admits that it has / will have a very real problem with the majority of its magnetic tape archives. This media is fragile. But then so are optical disks. As an aside it has been opined that well stored vinyl or shallac (78s) recordings are the best for archiving. Or even b&w film. In the above I'm not trying to belittle anyone's attempts to preserve important archival material. I am trying to do this with my own little collection of 'lost' BBC folk programmes (Folkweave etc.). But I have been researching the topic of suitable archival media for many years - and I haven't found an answer yet - apart from massive magentic hard drives regularly backed up. Anyway I refer folk to the following web sites: http://web.ukonline.co.uk/suttonelms/articles9.html http://www.prestospace.org/project/deliverables/D12-5.pdf http://news.bbc.co.uk/1/hi/entertainment/music/3940669.stm http://personalpages.manchester.ac.uk/staff/kevin.j.mullarkey/docs/PCtoDVDRGuide.pdf - especially see section 6 At the end it warns about the fragility of DVD disks - and the recommendation of using DVD-RAM disks in cartridges. Also to locate CDs/DVDs from different factories and make indentical copies onto each of these. The reaso is that CDs/DVDs from different sources may have different shelf lives - for example TDK and Kodak might be sourced from the same manufacturer say in Austria, but different from Sony in Japan. But there are hundreds of similar sites. It appears that there is BIG problem out there and DVs and CDs may not be the answer. Good luck. |
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28 Jul 09 - 03:12 AM (#2688573) Subject: RE: Digitising Analogue Recordings From: Peace There was a thread on which someone mentioned a disk exists which is purported to last for over 100 years. I do not recall whether the poster said DVD or CD. |
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28 Jul 09 - 03:40 AM (#2688578) Subject: RE: Digitising Analogue Recordings From: Will Fly Hi Chris - you're absolutely right that CD and DVD discs vary enormously in quality and staying power. The band I used to be in made an album on CD some years ago - copies of which were burned using semi-domestic equipment. I dug one out recently and it played exactly like a very old, scratched 78rpm record - totally unplayable. There were no obvious degradations on the surface of the CD - it just sounded like crap. To my simplistic mind, vinyl is actually one of the more stable media. I have discs going back nearly 50 years which have been looked after and which still sound great. My plan is to make mp3 copies for convenience (iPod, etc.), but never to get rid of the original vinyl like so many of my friends did when CDs first appeared on the market. Failing vinyl, the only answer for safe preservation seems to be - as you say - plenty of duplication in the archiving process! |
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28 Jul 09 - 03:51 AM (#2688585) Subject: RE: Digitising Analogue Recordings From: Phil Edwards Or keep an MP3 on the 'puter and don't burn it to anything. But take backups! |
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28 Jul 09 - 04:35 AM (#2688595) Subject: RE: Digitising Analogue Recordings From: treewind "take backups" - yes, and on what media? Actually, for audio, backups of .WAV files on CD are more reliable than audio CDs, because the CD-ROM format uses stronger error correction. But even then, CDs don't last for ever. Neither do hard disks... Anahata |
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28 Jul 09 - 05:50 AM (#2688626) Subject: RE: Digitising Analogue Recordings From: johnadams I attended a week long course on archiving put on by hatii at Glasgow University. The expert tutors were from all over Europe and included staff from the BBC and British Library sound archive. Horror stories abounded and the moral was always the same - multiple copies, vary the media and migrate digital content every five years. Vinyl has the best longevity, but properly stored analogue tape that's regularly spooled comes a close second. It's labour intensive and with the best will in the world a proportion of the content will be lost. Giving copies away to people helps to keep the stuff circulating an even if ultimately you lose some technical quality, at least the content survives a bit longer. |
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28 Jul 09 - 07:32 AM (#2688657) Subject: RE: Digitising Analogue Recordings From: bobad "Verbatim" claims an archival life up to 100 years for their CD-Rs, the kicker there being the "up to", I guess. |
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28 Jul 09 - 08:12 AM (#2688682) Subject: RE: Digitising Analogue Recordings From: PatMcGee Hi Chris, The best answer seems to be: Moveage (as opposed to storage). If you put something on a digital medium, plan to move it every five years. And, as other people have noted, make sure you've got multiple copies. Fortunately, with digital media, both of these are really easy. I've mostly finished transferring the FSGW recordings that were on CD and DAT. Out of 87 CDs and 14 DATs, so far I've recovered 83 CDs and 13 DATs. All but one of the CDs from back to 2006 played without any problems. A few from 2005, several from 2004, and probably a quarter of them from 2003 gave me problems. Before that, it looked totally random, probably less than a quarter. (To transfer them, I used either Exact Audio Copy on Windows, or Max on a Mac. These programs use the cd-paranoia library that promises a bit-for-bit good transfer if it's possible. When it sees read errors, it retries logs of times and does other things that most programs can't do. I eventually retrieved almost all the CDs by trying these programs on several different CD drives.) As for audio quality, the Library of Congress standard for digitizing tapes and other analog media is: 24 bit samples (CDs do 16), and 96,000 samples per second (CDs do 44,100). To do this requires an external interface, not using the internal sound cards. So it's a good thing that hard drives are really cheap and getting cheaper. We're gonna need a lot of them... Pat |
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28 Jul 09 - 08:54 AM (#2688704) Subject: RE: Digitising Analogue Recordings From: Jim Carroll I am in the process of digitising our collection, which numbers several thousand reel-to-reel tapes (some approaching 40 years old), hundreds of cassettes and vinyl albums. Once you have established an efficient copying set-up using the best of equipment available to you, the donkey work can be made routine. The problem, as has been indicated, is long-term storage. Our personal solution has been to get everything on a hard drive - then look out for places to deposit copies. Our own fieldwork is already in NSA at the The British Library (in London), and we are lucky enough to have two magnificent sound archives here in Ireland, The Irish Traditional Music Archive, and The Folklore of Ireland Society (both in Dublin). Eventually we hope that all our material will be deposited in these places. We are also helping to set up a local archive here in County Clare - another copy. I think the rule of thumb is to get as many duplicate copies of the collection as possible. I have to say I have been hugely impressed by the longevity of reel-to-reel tape, which has maintained its sound quality far more than I thought it would, though I did recently hear of n incident which underming this. A publican south of here used to be visited by one of Ireland's greatest fiddle players, now long dead. He systematically recorded the old man and carefully stored the tapes in a cupboard, out of harm's way. When he took his collection out to present it to an archive, he found that the cupboard had a heating pipe running through it; when the tapes were unreeled the coating stripped off like orange peel.. Jim Carroll |
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28 Jul 09 - 09:32 AM (#2688716) Subject: RE: Digitising Analogue Recordings From: mattkeen I think that in the long term the other problem with all archiving perhaps, is the "machine" used to play the archive on. Be that cuter, viyl, tape whatever. Will any still be around? So multiple formats is better from that point of view to |
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28 Jul 09 - 10:20 AM (#2688740) Subject: RE: Digitising Analogue Recordings From: johnadams Jim Carroll wrote: When he took his collection out to present it to an archive, he found that the cupboard had a heating pipe running through it; when the tapes were unreeled the coating stripped off like orange peel. This is a common problem and old tapes should never be unwound until they have been checked. If they are shedding oxide they need to be baked to consolidate the coating for a single pass transfer (hoping for the best). This is possible to do in an amateur way if professional facilities are not available - put them in a (fireproof) box with a 60 watt light bulb for 48 hours. The other test is to sniff the tapes for 'vinegar syndrome' - if they smell acetic then they need specialist attention. Otherwise tapes stored properly, tail out and wound and rewound once a year should last for a very long time. |
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28 Jul 09 - 10:48 AM (#2688759) Subject: RE: Digitising Analogue Recordings From: beardedbruce Having watched manuy of the archival tapes from the space program of the 1960s become unreadable, I will offer this observation: The only media tested and found to have a lifetime of multiple centuries was paper tape/mylar/paper tape. After over 500 years ( accellerated, of course) it was still mechanically readable. But as can be seen by the contents of the pyramids, sometimes you get lucky with other media. I favor etching onto a platinum/irridium substrate- even after the surface has worn off, the etching can be recovered by examination of the effects of cosmic rays on the material ( non-etched areas have less exposure) But for now, I think keeping multiple copies ( in whatever media possible), and spreading them around, is the best we can do. Look af the Doomesday Book- if it lasts a thousand years somebody else can make copies if they decide it is worthwhile. |
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31 Jul 09 - 07:54 AM (#2690975) Subject: RE: Digitising Analogue Recordings From: GUEST,Chris J Brady The 'lost Dr. Who episodes is an extreme case in point. http://en.wikipedia.org/wiki/Doctor_Who_missing_episodes Chris B. |
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31 Jul 09 - 10:08 AM (#2691033) Subject: RE: Digitising Analogue Recordings From: ChrisJBrady As an aside the BBC's Doomsday Project from a few decades ago was lost; the equipment to play the orginal laser discs went obsolete very quickly. Although there are (unsubstanciated) rumours that the content / masters may have been recovered or reconstructed, see: http://en.wikipedia.org/wiki/BBC_Domesday_Project I did hear that it is possible to rescue the content from corrupt CD/DVD disks using specialist equipment and software. Last year I received a scratched DVD that refused to play properly from Australia of 'Windjammer' (a Cinemiracle Widescreen (TodAO?) Film from the 1960s) that I had tried to get for very many years. I decided that the best thing to do was to back up the VOB files onto my PC and try and correct 'errors'. I used ISOBuster to do this. It took many hours due to the error correcting algorithms but I rescued most of the disk. Someone in the thread mentioned that CD/DVD disks from as late as 2004 had already gone corrupt!!!! There are specialist companies that can rescue the content from such discs. Apparently polishing the shiny surface helps. Doing a Google search will list quite a few. Many websites and forums also have advice on this. See: http://en.wikipedia.org/wiki/Dvdisaster Also: http://blog.tmcnet.com/blog/tom-keating/home-entertainment/fix-scratched-dvd-problems.asp Might I also recommend a mailing list devoted to the subject of digital archives at: HISTORY-DIGITISATION@JISCMAIL.AC.UK Good luck - Chris B. |
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31 Jul 09 - 10:30 AM (#2691050) Subject: RE: Digitising Analogue Recordings From: ChrisJBrady I quote from: http://www.domesday.org.uk/ It seems there is a big international plan underway to try and work out just how we can avoid losing access to digital archives. The pace of technological change is now so fast that we can't necessarily expect our current data storage media to be usable in 15 years. The UK Public Record Office hosted a conference in April 2003 called Practical Experiences in Digital Preservation, at which the Domesday Project (both original and 'resurrected' versions) was shown. [Electronic proceedings of Practical Experiences in Digital Preservation [##], including audio recordings of my, Paul Wheatley's and Adrian Pearce's presentations on the Domesday preservation projects.] [##] Note that the link does not now work http://www.pro.gov.uk/about/preservation/digital/conference/proceedings.htm However there is a huge resource of articles at the following website: http://www.nationalarchives.gov.uk/search/search_results.aspx?&st=q&aqgQueryText=preservation+++%22Digital+Preservation%22&queryText=preservation+++%22Digital+Preservation%22&searchText=preservation&queryType=ALL Or at: http://tinyurl.com/lrelp9 For an alternative perspective please check out an article by Richard Wright, from the BBC Archives, on an EC Project called PRESTO [$$]. This project looked at the archive and access issue from the broadcasters' perspective but has many useful analyses for a more general audience. [$$] http://www.cultivate-int.org/issue7/presto/ CJB |
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31 Jul 09 - 11:09 AM (#2691070) Subject: RE: Digitising Analogue Recordings From: ChrisJBrady Two other websites: 40th IASA 2009 Annual Conference - Sept. 20-25 2009 http://www.iasa2009.com/eng.html When IASA was founded 40 years ago few could imagine the realities with which today's audiovisual archives are confronted. As we approach the end of the first decade of the 21st century, the digital age for archives, libraries and museums is not an option, but a reality. Huge digitisation projects have been or are being implemented while at the same time the production and distribution of the new content is mostly digital. What is the role of the audiovisual archives in this new technological environment? How distinct are the roles of the various cultural heritage institutions? What methods and techniques will ensure the accountability and continuity of the audiovisual content? How have users' expectations been changed and what strategies have been employed to meet them? Which is the role of international organisations and of the IASA in this new environment? How can the National Archives of big and smallest countries can cope with this new environment? Conference Themes * Archives, Libraries and Museums. Moment of Truth - Time to Converge? * The disappearing Archive I: the loss of physical substance through digitisation * The disappearing Archive II: aging and physical deterioration of analogue media * The disappearing Archive III: obsolete carriers but no replay equipment * Born to die? Selection policies in the 21st century * Between archivists and users, taking advantage of the archive * Digital preservation and audiovisual preservation: Is there a divide? * 40 years of IASA * The role of the National Audiovisual Archives * Archiving the web and the new media audiovisual content * Ethics of digital archives ============== Creaing and Managing Digital Content Canadian Government http://www.chin.gc.ca/English/Digital_Content/ ============== |
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31 Jul 09 - 12:14 PM (#2691110) Subject: RE: Digitising Analogue Recordings From: Bernard Sadly, there is little that can be done for a CD/DVD where the recording substrate (dye) has failed, usually because of exposure to light (ultra-violet is the usual culprit). You can slow this process down by storing them in light-tight containers, but it's by no means a complete solution. One that 'sounds like an old 78' has probably suffered this fate - no amount of polishing of the shiny surface will make any difference whatsoever - that only works for real scratches, not missing data. For this reason, any time I buy an artiste's CD that isn't a glass mastered pressing, I have no qualms in burning a copy straight away, and backing it up in MP3 format! I've seen quite a few fail - and sometimes we only find out when we're playing them on air! |
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31 Jul 09 - 01:05 PM (#2691141) Subject: RE: Digitising Analogue Recordings From: Arkie Mitsui makes a gold CD and DVD which it markets for archival purposes with an expected life of 300 years. Tests have been run to determine this figure and in 300 years we will know how reliable these discs are. They certainly should last longer that the average CD-R and there is certainly a range of reliability in commercial CD-Rs. Known enemies of CD-Rs are heat and light and mishandling. Hard drives are suspect for long term storage since they reportedly become unplayable in time particularly if not in use. They become unplayable when in use as well. I have lost a couple or hard drives in the past ten years. The key is not only media but multiple copies. When I was running a digitizing project at work we saved to the Mitsui Gold and made copies on at lest two other brands as well as keeping a hard drive copy. The key is backups; checking the backups, and a plan to migrate data periodically. The upside is that once the migration is made from analog to digital, the next migration will be simpler and take less time. We were also careful to make sure the music tracks being saved were properly tagged. |
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31 Jul 09 - 01:27 PM (#2691156) Subject: RE: Digitising Analogue Recordings From: GUEST,punkfolkrocker please suggest any good reliable current version PC software [preferably freeware] that can quickly & effectively check CDs & DVDs [home burned and commercial pressings] for errors and recoverability. I've already made visual inspection of my music collection and sifted out several hundred early to mid 90's commercial pressed CDs that display evidence of bronzing discolouration and pinholes in the metal layer. So would now appreciate recomendations for a good software that can quickly * and easily check individual discs for any potential playback errors. [* minutes rather than hours per disc] cheers... |
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31 Jul 09 - 01:46 PM (#2691162) Subject: RE: Digitising Analogue Recordings From: GUEST,punkfolkrocker ..and a fair few home burned DVDs that are starting to look a bit suspiciously 'cloudy' opaque.. |
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31 Jul 09 - 02:01 PM (#2691169) Subject: RE: Digitising Analogue Recordings From: treewind cdparanoia might be good for checking your audio CDs It's usually used for ripping audio tracks, and it tries very hard to get it right, re-reading anything with errors and reporting on the various types of error, correctable or not. You can redirect the output to /dev/null if you don't actually want the recovered .WAV files. For data CDs and DVDs, tar cf /dev/null /dev/cdrom or similar should do the trick. Totally free software, of course, including the OS they usually run on... Anahata |
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31 Jul 09 - 03:22 PM (#2691214) Subject: RE: Digitising Analogue Recordings From: ChrisJBrady For checking and correcting CD/DVDs see: http://blog.tmcnet.com/blog/tom-keating/home-entertainment/fix-scratched-dvd-problems.asp Also Google search 'dvd repair' or 'dvd check' Or try http://groups.google.co.uk/groups/search?q=repair+dvd Try RecuePRO - which is one I used to recover Windjammer. Good luck. |
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31 Jul 09 - 06:42 PM (#2691296) Subject: RE: Digitising Analogue Recordings From: Gurney I have never seen any discussion of the durability and/or longevity of solid-state devices. Thumbdrives are fairly fragile, -as when brushed against whilst sticking out of a computer- but as cards and thumbdrives are getting very cheap, and I'd like to know if they are a viable option. Of course, again we need drivers for them, which are almost invariably on CD in case computer technology leaves them behind. I have one old thumbdrive that works on nothing, because I've lost the driver. My own small collection of cassette tapes have deteriorated noticably. They were kept at room temperature. Even the fibre-tip ink I used to label them has mostly gone. Paranoid photographers used to store film in refrigeration. |
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31 Jul 09 - 09:36 PM (#2691373) Subject: RE: Digitising Analogue Recordings From: Ross Campbell Refrigeration was appropriate for unexposed film, especially in hot, humid climates. Reducing the storage temperature reduces the rate at which the film's chemical medium deteriorates. Once exposed, film would still need to be kept cool until developed, after which normal temperatures would be OK. I've had a couple of conversations recently where it was suggested that any digital duplication, whether from CD to CD-R or from hard drive to CD-R, would result in an exact copy. In the light of the above, I'm beginning to doubt that. I usually use Toast (on a Mac) for copying to CD-R, but that only does a read-back comparison for data-files. A recent problem I have found is that certain CDs may only be copied at real-time speed. This could be due to limitations of the reading drive on my desk-top machine, now about ten years old. I tried to get round that problem by transferring the CD first to the hard-drive on my lap-top, where it appears as a folder containing the expected number of audio files. Attempting to copy that folder to a blank CD-R produced an "insufficient space" message. Transferring the files individually brought the same result. So how come 69 mins of music won't fit on an 80-min CD-R? Ross |
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31 Jul 09 - 10:11 PM (#2691383) Subject: RE: Digitising Analogue Recordings From: PatMcGee I used Exact Audio Copy on a Windows machine to read those CDs. It uses the cd-paranoia library, mentioned earlier. On my Mac, I used Max, which also uses cd-paranoia. To check a CD, run EAC and check the error log. If it reports no errors, you're OK for now. Then you can throw away the wav files it extracted. If there are no errors, EAC will finish pretty quickly. If it doesn't finish quickly, then you don't need to look at the error log. You already know something is going bad. But, if you're going to go to that trouble and the CD is worth saving, buy two or three 1 TB hard drives and save the files. You can probably save 1400-1500 CDs on the drives. Two drives because you want two copies. If you get three, then when you compare one against another, you'll be able to tell which of the three copies is correct. (two votes against one.) After my recent experiences trying to read those CDs from the concerts, I've completely given up on the idea of CDs or DVDs lasting more than a few years. Sure, most of them did.... |
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01 Aug 09 - 02:24 AM (#2691429) Subject: RE: Digitising Analogue Recordings From: Gurney More and more artists are burning their own work, and I have had a couple or three pre-recorded CDs which have deteriorated into unplayability. One silver side peeled off and left me with a tranparent disk! One artist I approached with this problem said "Oh. That's interesting." And walked away! It's always the ones that you don't want to lose. |
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01 Aug 09 - 04:43 AM (#2691468) Subject: RE: Digitising Analogue Recordings From: GUEST,John Archer The point about a song being a folk song is that it is one which survives the selection process. Thus it is a song that a multitude of people have learn and sung, a song that many of them have recorded. If a song is lost to posterity because only one person has ever sung it, and only one other person has recorded it, on a cheap and nasty CD which self-destructs ten years later, and no one else can sing that song from memory, then it ain't a folk song, and so it doesn't matter if it has been lost. |
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01 Aug 09 - 05:39 AM (#2691491) Subject: RE: Digitising Analogue Recordings From: johnadams Sometimes it's the performance you want to save for reference. |
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01 Aug 09 - 06:35 AM (#2691517) Subject: RE: Digitising Analogue Recordings From: treewind Gurney: solid state devices I believe flash memory cards (SD cards and USB pendrives) are not a particularly reliable medium for long life storage. I'm considering using them instead of DAT for server backups, where the media would be re-used on a fortnightly or monthly basis, but I wouldn't trust them them to hold data for years. Ross: "it was suggested that any digital duplication, whether from CD to CD-R or from hard drive to CD-R, would result in an exact copy. In the light of the above, I'm beginning to doubt that." With Audio CDs it is possible for errors to creep in. When part of a CD had to be re-read, the player relies on heuristics to stitch together the block that's just been read and the data than went before, by reading from just before the problem area and matching the overlapped portions. Also with uncorrectable errors a CD player will use an interpolation mechanism that approximates the recovered audio. With hard disks and CD-ROM format, you know exactly where each block starts and strong error correction and detection mechanisms means the likelihood of errors is infinitesimal. Sure, the CD-ROM surface can deteriorate and become unreadable, but the computer reading it will either get it right or it will declare it unreadable. That's why I suggested earlier that .WAV files on CD-ROM are safer than audio tracks - if you can copy them, you know your data isn't corrupt. Anahata |
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02 Aug 09 - 06:33 PM (#2692456) Subject: RE: Digitising Analogue Recordings From: GUEST,David Barnert The current crop of Macintosh computers cannot open MacDraw files created in the 1980s, not because of file degradation but because of the evolution of format standards. A file archived on a DVD that will last for a hundred years won't do anybody any good if within twenty years nobody remembers how to differentiate it from a random stream of bits. |