For a current list of degrading analog tapes, click here.
For several years, we have been discussing the differences between Sticky Shed Syndrome (SSS) and Loss of Lubricant (LoL). It appears from my latest research (presented at the 2006 Audio Engineering Society’s 121st Convention in San Francisco in October) that LoL does not really factor into the equation for most tapes and that an overarching failure mode is Soft Binder Syndrome, or SBS. Sticky Shed Syndrome appears to be a subset of SBS.
I receive many tapes that use very creative methods of securing the end of tapes to reels. Some don’t do it at all. Most 1/4-inch tapes are secured as shown below. Sadly, the superior Zebra tape is no longer available. This is the traditional crepe-paper type of tape sold for the application. The picture below should explain all.
I have been suggesting for many years that one of the reasons that acetate audio tapes have not suffered from vinegar syndrome to the extent that acetate films have suffered from this malady is because of differing storage practices. In general, film for many years was stored in sealed cans while tape has generally been stored in cardboard boxes.
I recently came across a 3-inch reel of acetate tape, not in its original box, that showed the following pattern in the box. This tape was recorded in Fall of 1964 and the photo was taken on October 2006, 42 years later. The tape played well, considering it was originally recorded at 1.88 (1-7/8) in/s.
All of the outgassed material that was absorbed by the cardboard was no longer free to degrade the tape.
Often a tape comes in for restoration that has been poorly wound or poorly stored. Here is an example:
One of the interesting things about this particular tape was it had been recently wound on a constant-tension professional machine prior to shipping to me.
We think that the entire tape had not been re-wound, allowing the higher tension wind to compress the inner core slightly, causing this cinching. After transferring the tape (which didn’t show much ill effect for its cinching), we still found it difficult to get the tape to wind smoothly on the reel.
Therefore, our current suggestion is if you find a tape like this, do not rewind it and attempt to clear up the cinching unless you are also ready to transfer the tape, as there are no guarantees that it can be wound better after unwinding.
Please see this post for an update (2008-02-15).
MINIMUM Tape Handling Requirements Checklist
This checklist is not a complete guideline. It contains only those items that experience and testing show will have an immediate or severe effect on magnetic tape. Failure to adhere to the items on this list may cause premature loss or deterioration of magnetic tapes and should be considered misuse of the medium. These are minimum handling requirements that summarize good practices.
I made this chart to show how the different standards and recommendations for media storage overlapped. Click [or save target as] for the full-size image.
This is a general article to provide some information on the subject. More should follow.
For a current list of degrading analog tapes, click here.
There are multiple modes of degradation and it depends on the type of tape.
Acetate Tape
Polyester tape
Obviously all tapes can suffer from mechanical damage and poor winds.
I expect to be discussing aspects of this in greater depth, but it is a complex subject and contradictory reports have been generated.
The question of how to format hard disks (i.e. what file system to use on them) for easy interchange is another FAQ. A recent experience brought home the fact that it is more complex than one might hope. The computer industry is headed towards universal readability, but it is not there yet. The most-able-to-be-read-and-written format appears to be FAT32, although my friend Eric Jacobs makes the point that NTFS is a more robust hard disk file system, and I have to agree.
In 2006, I wrote a blog post (here) called “Let Sleeping Tapes Lie: What to do with poorly wound tapes”. For years, tape experts have been suggesting that it is not as good an idea to rewind tapes as was originally thought. This was partially based on the fact that most rewinding in archives was done on the oldest, junkiest machines so as to not wear out the good machines. Unless rewinding is done on high-quality tape transports, it is indeed counter-productive.
We continue to receive poorly wound tapes and are able to play them successfully. So why the quandary now? The reason is that I read portions of another Bharat Bhushan book, Mechanics and Reliability of Flexible Magnetic Media, 2nd Edition, New York, Springer, 2000. Referring to several research papers he makes a compelling case that tapes should be rewound annually if subject to storage environment fluctuations and every 3.5 years if kept in a climate controlled storage area.
We are currently working on some un-published tapes for a major Canadian folk artist. We have a 7.5 in/s 2-track stereo recording that was one of (if not the) first studio recording of this artist from circa 1972.
At some point, this tape was played on a 1/4-track machine that injected hum onto the left channel. Here’s what the magnetic viewer showed:
There was yet another discussion about winding tapes for long term storage. This time it was on the Society of American Archivists list. While it was focused on VHS tapes, where it was decided that it was more important not to leave the tape in the middle with active content exposed, some discussions of the mechanics arose and I have added them as comments to the original post, which is available here.
We had success transferring two reels of one-inch Agfa PEM-469 tape that was shedding and leaving a waxy clear-to-yellow exudate on everything. We were happy to get through these and recover the content. This is discussed in more detail towards the bottom of our Degrading Tapes page—hopefully the most up-to-date resource on the Web about problem tapes. Please let me know if you would like to help me add anything to the page. It is there for everyone struggling with old degrading tapes. If you haven’t looked already, please look at my paper on the subject.