[filmscanners] Re: PS sharpening

["David J. Littleboy" <davidjl@gol.com>]

"Anthony Atkielski" <anthony@atkielski.com> writes:

>>>>>>>>>
In theory you can also downsample in one step and unsharp mask once, but
then you must calculate the proper radius based on the number of pixels lost
and unsharp mask up front.  For example, if you downsample in one step of
500%, you'd use a radius of 4.9 pixels or so.  I don't do it this way so I'm
not sure how it turns out (it's easier to unsharp mask in steps afterwards,
and look at the partial results after each step), but you can always try it.
<<<<<<<<<<<

Just to clarify here: the sharpening with radius of 4.9 pixels or so is
applied _before_ downsampling by 500%, obviously. Right?

As I understand it, there should be N + 1 sharpening operations for N
downsampling opertions. In some sense, the first N sharpening operations
have a different purpose than the last: they're to make sure the
downsampling retains the detail (and contrast) you want. The last sharpening
is to make the final image look good.

As usual, correct me if I'm wrong. (So far, I've been quite lazy, and simply
let Qimage do the resampling for printing. Thus I simply create an image
file at the native resolution of the scanner/camera, adjust and sharpen to
taste, and let Qimage print it.)

David J. Littleboy
davidjl@gol.com
Tokyo, Japan



----------------------------------------------------------------------------------------
Unsubscribe by mail to listserver@halftone.co.uk, with 'unsubscribe 
filmscanners'
or 'unsubscribe filmscanners_digest' (as appropriate) in the message title or 
body