Re: Unsharp mask was Re: filmscanners: Getting started question

["Dave King" <kingphoto@mindspring.com>]

> on 7/15/01 5:37 AM, Arthur Entlich wrote:
>
> > Lastly,  I have found the amount of USM you can get away with
depends
> > upon the scanner and the film in use.  If the scanner or film
tends to
> > exaggerate grain, defects, or noise, you can't go to far with USM,
> > because
> > these are indeed the types of things that USM will "enhance".  If
your
> > scanner has low noise, doesn't grain aliase, or exaggerate dust
> > scratches
> > and the like, you can pump the USM up a fair amount without it
looking
> > unnatural.
> >
> > Art
>
>
> Also the subject matter. Fine details (high frequency) vs broad
areas (low
> frequency). Bruce Fraser uses a tree branches and a pumpkin to
illustrate
> the difference in Real World PS. An image primarily composed of fine
details
> may want a smaller radius with a high(er) amount, relative to a less
> detailed object, which in turn may want a larger radius with a lower
amount.
>
> Todd

Or one can use the simple approach of sharpening "grain" (or whatever
it is:) with no regard to individual image detail.  I prefer to look
at the grain in an area of no detail in fact, at 100% at the final
print size.  I've been using 75% at .8 radius, 0 threshold for most
things with the Agfa T-2500, and sharpening the original scan once and
then again if the image has to be interpolated up considerably for
large print sizes.  This seems to me to be closest to an "analogue
feel" in the final print, but it does throw away one of the advantages
of digital that many people love.

I've found in comparisons of Genuine Fracticals to Photoshop bi-cubic
(in two stages when much upsampling is needed) that Genuine Fracticals
introduces edge sharpening effects that are not "analogue like", and I
prefer bi-cubic.  Also, in areas of complex detail (grass for
example), GF can get confused and make a bit of a mess of things.
Even so, I've found the differences between GF and bi-cubic to be
pretty subtle in the final print.

Dave