Re: "Pepper grain" (was Minolta Multi Pro)

[rafe.bustin@xxxxxxxxxxx]

On 5 Apr 2002 at 1:44, Arthur Entlich wrote:

> 
> 
> byard pidgeon wrote:
> 
> > WOuld also be nice to know if the prints were made with condenser or
> > diffusion.
> > 
> > Also, I wonder if the pepper grain and bubbles show as much if one enlarges
> > the neg/slide to final size during the scan, rather than in an image editor?
> 
> 
> Are you referring to upsampling via an image program, versus using the 
> native scanning optical scan resolution?  I would expect upsampling 
> would tend to emphasize the aliasing, but that might depend upon the 
> method of upsampling used.


Gee, for a moment, I thought you "got it."

Aliasing has to do with the bandwidth of the input, relative 
to the sampling rate.  Nothing more and nothing less.

Any input with a frequency content beyond (sampling rate / 2) 
leads to aliasing.  That's all there is to it.

"Upsampling" is post processing of the sampled data.  It's usually 
just a euphemism for interpolation -- taking a best guess at what 
the data "might have been" with a higher sampling rate.


rafe b.

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