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Re: [ARSCLIST] Preservation media WAS: Cataloguing still :-)
steven c wrote:
Well, there is an upper limit to the accuracy of any analog data-storage
technology...if nothing else, the molecular qualities of storage media
define a limit (albeit a VERY large one!). In fact, I would suppose this
would also apply to digital media?!
Digital media incorporate error correction in order to reduce the
probability that an error will affect the result. In fact, the raw error
rate of digital recording tends to be very high, but layers of ECC
reduce it essentially to whatever resulting rate is acceptable.
the accuracy of a photographic image is limited by the "grain," or
the size of the particles which react to light...likewise, the
accuracy of a scanned image is limited by the number of "pixels"...
which in turn is dependent on the density of light-detecting entities.
For some reason, none of this discussion (at least, none that I've read)
dealt with the other dimension of resolution, the depth of the signal.
We are accustomed to an eight-bit scale (24 bits for three colors) on
images since that is more than one can usually see in a print, but more
can be used just as a scale with more than 16 bits can be used in
capturing audio. This would then get into elaborate discussion of
half-tone printing, linearity of dye sublimation and more than I believe