Archived posting to the Leica Users Group, 2007/08/18
[Author Prev] [Author Next] [Thread Prev] [Thread Next] [Author Index] [Topic Index] [Home] [Search]I'd file this under BS.
Even if it were marginally true, which I doubt, it
would be the province of the sort of techno-dweebs who
agonize over angels-on-pinheads type issues.
Let's make pictures.
--- Lawrence Zeitlin <lrzeitlin@optonline.net> wrote:
> On another list someone complained about the
> "posterization" and
> aliasing encountered in scanning Tri-X film. Here is
> the quote:
>
> "both my 2880ppi and 4000ppi
> film scanners posterize my Tri-X negatives... which
> makes sense. there is also nothing you can do to
> remove sampling errors after you scan. My early
> analysis of Tri-X grain showed that it has strong
> frequency content around 4000ppi so when my scanners
> sample at around half the Nyquist frequency the
> aliasing is just a fact of life. With finer grained
> films, the grain is still aliased, BUT since the
> signal to noise ratio is so much higher the actual
> useful *image* data is not lost and *luckily* the
> new
> aliased *grain*, while not an accurate
> representation
> of the original, is still aesthetically pleasing."
>
> Can someone explain what he means in plain language?
> I've scanned
> hundreds of Tri-X negatives with my Minolta Dimage
> 5400 scanner at
> 4000ppi, and, apart from the inevitable dust spots
> on poorly stored
> negatives, I have yet to see what he means. If there
> is a problem, is
> the scanner software correcting it automatically?
>
> Larry Z
>
>
>
>
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>
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