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[filmscanners] RE: another Sharpening question



Paul,

I did not realize that it could be used that way.  I would think that such
use would be really limited and dependent on the subject matter and what one
wanted to do with it.  While it might enhance localized contrasts, it is an
uncontrolled enhancement of all local contrasts in the image as contrasted
to localized in the sense that one selects the different elements and
selections in the image that oe would want enhanced, leaving the unselected
alone.  In that sense, it is almost like using the contrast adjustment in
Photoshop.

filmscanners_owner@halftone.co.uk wrote:
>> From: Ed Verkaik
>>
>> Just imagine a typical sky -- either one with cloud elements and
>> blue sections, or cloudy with varyiong degree of light and dark
>> areas (stormy sky).  Surely there are generalizations we could apply
>> to such subjects?  I always assumed that since clouds have no
>> natural "edges" that sharpening is not relevant and maybe even
>> detrimental.  Unfortunately, my limited vision does not detect fine
>> changes in contrast or sharpness.  In a perfect world, I would try
>> to come up with a single (mild) degree of sharpening to apply to all
>> images, either through an action or with dedicated software.  I'm
>> hoping the experience of others can lead me to a solution.
>
> Actually, I should make one further point, which is that Unsharp Mask
> can also be used as a localized contrast enhancement, by setting its
> diameter to something near its maximum value, rather than to the
> usual very small value. This is particularly useful when you want to
> enhance local contrast (perhaps even in clouds), but you have too
> much overall dynamic range to use a more conventional Levels or
> Curves approach. If all you have is clouds, though, Levels or Curves
> should work fine.
>
> But that use of Unsharp Mask isn't really sharpening.
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