> Brad then goes on with a plan to make many redundant copies
> with some crypto to ensure that the Bits are as they were at
> the time the Digital document was "frozen In time"

Actually a one-way hash is not strictly speaking, cryptography.

Thinking of it as a digital thumbprint is probably the best way
of metaphorizing it.
>
> I am afraid that I have one foot in each camp!
>
> To store a document as a analog format - implies, at least for
"visual"
> documents (like microfilm) that someone who stumbles across
> the information, armed with no more than a Magnifier and
> sense of curiosity can it least identify that they do indeed
> have a document in their hands. Further, they can use
> whatever image technology that exists at that time and make
> themselves a copy of the document. 10 years ago it would
> have probably been a reader printer, or even a darkroom
enlarger.
> today it might be a digital camera with a stack of Closeup
> lenses, how knows what it would be tomorrow.

This depends on what you grew up with, I guess. The notion that
there will be analog imaging equipment to use is begging the
entire question.

> The analog format would reveal the gist of the data to anyone
> without them having to know the format or how the document
> was created. (Word
> 3.2 for DOS or An Underwood Upright)

That limits access to those who have physical access to the
materials, and if that is your criteria, used a scanned image.

> The meta data would depend on how the copy was documented,
> and No one could not really prove that it was indeed made at
> a given time, or that it is really authentic.

Normally the emphasis is in the other direction.


> Converting the information to Digital, or retaining the
> digital source and replicating it over a diverse network Does
> perhaps offer the ability to use Crypto to be able to declare
> that this version WAS saved by John H. Smith on PC 3456786 on
> October 27, 2006 at 23:10 EDT

I cannot think of any other method of verification that can
compete with digital time stamping.

> Depending on the format that may be all you get. If the file
> was saved in a documented format like Open Doc, and that
> format has been maintained, and If the user has a current
> version of the filters and IF they can tell from the metadata
> that the document may be of interest.
> Then the digital document may unfold with perfect clarity.
> If any of the links are broken, it is just so many almost
random bits.

That is untrue. I speak as a person who has written numerous
conversion programs for documents in unknown formats. If the
information is there in digital text format, in either ASCII or
EBCDIC, it is generally possible to reconstruct the document
text.

> Note that a Microfilm copy even if scratched and bent,
> suffering for Vinegar Syndrome, Re-dox and too much
> thiosulphate, can probably still be read. at least enough to
> see if you want to treat those problems. A damaged - or
> unsupported format digital document may not give that freedom.

It is far, far easier to do a digital conversion of a digital
document, than build a special piece of equipment to convert an
analog recording of some kind. And since the document is digital,
it can be passed around at no incremental cost to many people who
might have both the interests and capabilities to do so.

> As far as Video, "Film", audio and other data, again they can
> only be used if the format is known. and if the playback
> equipment is available or can be faked.

Again, this is untrue. When an image is converted to digital, it
becomes one of a small subset of values : on off bits, 0-255 grey
level, or individual color level values (typically three bytes,
0-255 of red, green, or blue). The various image formats compress
those values in different ways, and use different algorithms for
motion encoding. But if you scan an image of a document page at
8-bit grayscale, it will be digitally recoverable and legible ten
thousand or a hundred thousand years from now.

No scratches, no fading, no deterioration of any kind. And while
there was a lot of ad-hoc experimentation with formats in the
early days of imaging, this has really settled down. You can
expect a JPG to be readable by current software a thousand years
from now, even if it is not the method currently used for picture
taking.

The compression methods such as LZW are based on mathematical
formulas and algorithms. Those will not change in the next
billion years - pi r squared is as true today as it was two
millennia ago.

Digital media offer lossless data transmission, and no
generational decay (such as in analog copying of photographs.)

> (a Film Scanner can
> be used to transfer a 16mm Movie film if the original projector

> is no longer available.

But the film has a finite lifetime. Digital data is eternal. It
does not decay.

> A video tape is more likely to have
> its hardware to be not available, and so if it is in a
> documented digital format that may be the way they the future
> user will recover it.
>
> But if the Motion Picture exists as say a 35mm Negative in
> good shape, the future user could scan it into the then
> current system, at what will probably be better colour depth
> and resolution than a scan made today for HDTV, let alone NTSC.

> --
> Charles MacDonald Stittsville Ontario
> cmacd@... Just Beyond the Fringe
> http://www.TelecomOttawa.net/~cmacd/
> No Microsoft Products were used in sending this e-mail.

One of the movie DVDs I bought or rented recently was digitally
remastered from an old film copy, and the before and after
differences were amazing, where they fixed scratches, fading,
etc. I'm sorry I don't remember which one it was, I'll see if I
can find it again.

The archivists of the next generation, 25 years from now, will
tear out their hair and weep over the delay and foot-dragging
that is occurring today in digitizing media.

Digitizing makes media universally available to each of the
billions of people in the world who has access to the Internet.
It reduces the cost of copying and transferring the media
(including documents) to near-zero. It makes the information
electronically searchable, which makes it far more useful. And it
eliminates the degradation of the content over time to zero.

The only reasons I can think of for not digitizing are
unfamiliarity with the technology, and nostalgia. It is
understandable that nostalgia might be forgiven archivists - but
your own successors will not forgive you.

Brad Jensen