Video Art / Media Art Preservation:  Studies and Suggestions                      THE DANISH VIDEO ART DATA BANK

Tape Analysis and Evaluation

 
The first step toward preservation is of course that you are able to effectively analyse and evaluate the conditions of videotapes in collections/archives. Not only you have to know

1. The physical properties of videotapes
2. the factors/conditions to tape detoriation … but also
3. how to discover and identify the signs of detoriation

Ad 1) I will not describe the physical conditions: how a tape is build up, but refer to the Internet, where you may find technical descriptions of the physical properties (1)

Ad 2) The factors leading to detoriation I have already dealt with earlier today.

Ad 3) You can also find descriptions of different ways to identify signs of detoriation on the Internet. I will though try to summarise what you cab do.

Inspection of Video Tapes

To put it very short: you do it through visual inspection and playback.

 If you can see that the tape is not wound evenly – and this could be coursed by starting stopping the playback on and off, using high speed fast forward/rewind or a poor adjusted playback machine - you should first rewind it properly and then evaluate it through playback. With an open reel tape you might also be able to discover chemical detoriation. This is difficult to evaluate visually with tapes in cartridges.

Using playback you should be able to evaluate problems like video and audio noise, intensity of blips, timing problems, colour shift/distortion and audio problems.

The American firm SPECS BROTHERS Audio & Video Tape Restoration authored the following 7-Step Physical Inspection Plan for the American National standards Institute Subcommittee on Magnetic Tape as simple and basic inspection process to sample conditions of magnetic tape:

1.  Check physical container for damage that compromises the structural integrity of the container itself

2. Check the interior of the container and the edges of the tape for patterned black, brown, or mustard coloured contamination and for fuzzy or thread-like grows that indicate the presence of fungus

3.  Smell the tape as soon as it is removed from the container for abnormal smells

4.  With light source above and slightly behind tilt the tape edge-on at approximately 45 degrees away from the light source and inspect tape pack

5.  Check the tape edges and the reel/cassette/cartridge for particulate contamination and for signs of staining that may indicate liquid contamination

6.  Check the tape edges for white powder or crystalline residue and check the interior of the container for black/brown flakes of oxide

7.  If the tape is reel to reel, allow a few outer wraps to hang loose and examine for physical distortion and binder/base adhersion failure.

You can find these 7-Steps more elaborated in the essay ”White Paper” at the SPEC BROS web site  (2).

Notes:

(1) Try for example: http://www.clir.org/pubs/reports/pub54/2what_wrong.html

(2) http://www.specsbros.com/whitepaper.html