[Table of Contents]

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: [AV Media Matters] Long-term presentation: digital


Nicely put!

One correction.  IPI is located at the Rochester Institute of Technology and
is not a Kodak company.  Kodak funds some of the research at IPI.  IPI will
test digital videotape if you give them the money.  They may draw the line
testing clay or stone tablets.

I have been an advocate for digital technology for about 20 years--when I
first started work on the Ampex D2.  As an archival medium, digital has the
advantages of being able to produce copies with essentially no degradation
quality.  The other great advantage of digital is that you can monitor the
video quality via error rates.  You can track this over the years and
transfer any tape that has an increase in error rate.

With two Ampex D2 machines, I made 40 generations and the 40th looked just
like the original.  With analog, the best machine was the Ampex VPR-3.  We
made 16 generations with VPR-3s with very little noticable video degradation
after the 16th copy.  An incredible feat.  That was the result of the
brillant video engineer--Al Trost (who I will have lunch with tomorrow).  Al
learned by doing.  He had no college training.

The problem with long-term preservation is not whether or not it is human
decipherable, analog, or digital.  It has to do with how the medium is made,
how it is stored, and if playback equipment is maintained.

Film is a good archival medium if you can afford it and you store it in a
deep freeze.

Videotape has two major archival problems; binder stability and format
obsolescence.  Format obsolescence is an issue with ALL new technologies.
The binder stability problem can be overcome, to some degree, by storing the
tapes at 25 percent RH and at a temperature below 70 F.  Some of the tape
manufacturers now make products with a reasonable long-life binder but you
have to ask them which tapes are archival.

Format obsolescence is not as bad as some people claim.  If the format is
defined (as in a SMPTE standard), a playback machine can be built a hundred
years from now with totally different technology.  Yes, it would be
expensive, but doable.  The SMPTE standard describes everything you need to
know to reproduce the tape.  That's why I do not recommend non standard
formats for archival material.

Compression is another issue.  Formats that use compression should not be
used as an archival medium.  But, they can be copied--provided the two
machines use a common "language".

I hope you realize that this makes clay and stone look appealing.

You make a good point about access vs preservation.  Archives must make the
material accessible  To me, S-VHS is a good access format and it will be for
many years.  DVD will eventually take over but who knows when?

Jim Wheeler

[Subject index] [Index for current month] [Table of Contents]