Those arent really artifacts, that is what the sharpening is and was meant to be (just done too far). It is nothing like jpeg artifacts that introduce new tonal changes and color shifts that do not correspond to the image. Noise is "changes in tonality" that are normally not very visible. USM with too small a radius or threshold will accentuate those small changes more than they accentuate the actual image boundaries like they should. This is especially true when the noise is a much smaller size than the imagery (4000dpi+ scans) (I know I just made it more confusing for a lot of people probably, sorry) -mh --- In DigitalBlackandWhiteThePrint@y..., SKID Photography <skid@b...> wrote: > mh@t... wrote: > > > Digital noise is not the same thing as artifacts from USM but everyone > > should be aware that too much (or improper) USMasking can make normally > > low-visibility noise more visible. > > I disagree. Yes, one can make low visibility 'noise' more visible with over sharpening, but it's much more > than that. > > What you are making (by over sharpening) are 'halos' or some such artifacts around changes in tonalities. It > is *not* 'noise', and by using the improper terminology one just confuses the issue. > > Proper terminology is really important when discussing problems on a list like this. > > Harvey Ferdschneider > partner, SKID Photography, NYC > > > > > > > > > > > > Digital 'noise' is not the same thing as the artifacts one gets from using unsharp mask, and should not be > > > > > confused. I think there is a different term to use for the USM artifacts, although I don't know what, > > > specifically, to call them, beyond 'artifact' or 'halo'. > > > > > > Harvey Ferdschneider > > > partner, SKID Photography, NYC > > > > > > > > > [Non-text portions of this message have been removed]
Message
Digital noise or sharpening artifacts? was, Re: Grain on B&W film??
2001-11-13 by mh@toomanyartists.com
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