Re: [ARSCLIST] Preservation media WAS: Cataloguing still :-)

[Don Cox <doncox@xxxxxxxxxxxxxx>]

On 03/09/06, Mike Richter wrote:
> 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.
> 
>> For example,
>> 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 fits here.

Most scanners now measure more than 8 bits per channel, and so I think
do cameras. The limiting factor is the computer monitor - these are
still low resolution devices, limited to three 8-bit channels.

Regards
-- 
Don Cox
doncox@xxxxxxxxxxxxxx