[filmscanners] Re: Grain aliasing
Yes. The new Fuji Provia F series of films use what I would refer to as a "soft edged" grain, which, in effect is "antialiased" to begin with. This provides a softer transition and is similar to defocusing the grain slightly. Velvia, on the other hand, while slow and fine grained and great for some applications, tends to have very highly saturated color and dense shadows, and leads to both higher aliasing and more noise in shadows. Art [EMAIL PROTECTED] wrote: > Interestingly, I seem to get a good deal of grain/aliaing with Velvia as > opposed to ProviaF 100 or 400. Has this been the experience of others as > well? > > Howard > [EMAIL PROTECTED] > Unsubscribe by mail to [EMAIL PROTECTED], with 'unsubscribe filmscanners' or 'unsubscribe filmscanners_digest' (as appropriate) in the message title or body
[filmscanners] RE: Grain aliasing
Test only - ignore please. George Harrison Unsubscribe by mail to [EMAIL PROTECTED], with 'unsubscribe filmscanners' or 'unsubscribe filmscanners_digest' (as appropriate) in the message title or body
[filmscanners] RE: Grain aliasing: Thoughts, solutions?
I don't know how Vuescan works, but in NikonScan, once you've done an autofocus, you can bump the focus slider manually. Since there's already an uncertainty of at least a half a count, I'd try bumping it by two, to see if that helps. However, I'm not sure defocusing will reduce aliasing, because it probably has a rectangular response shape (meaning that it turns a dot into a sharply defined circle, not a fuzzy blob). What's really needed is a diffuser. NeatImage is a fairly low-cost investment, and I've had some good results with it. -- Ciao, Paul D. DeRocco Paulmailto:[EMAIL PROTECTED] > From: Peter Klein > > What do you think would be the most effective thing(s) to do? > Some thoughts > come to mind: > > - Pick up a used SprintScan 4000 (no ICE/GEM, but affordable and > less prone > to show dust, etc.) > - Get Neat Image. > - Blow big bucks on an LS-4000 > - Learn how to slightly defocus the LS-2000. (I've heard this takes a long > time to accomplish). Unsubscribe by mail to [EMAIL PROTECTED], with 'unsubscribe filmscanners' or 'unsubscribe filmscanners_digest' (as appropriate) in the message title or body
[filmscanners] Re: Grain aliasing: Thoughts, solutions?
You are correct. Once the errors have been incorporated into the file data, it takes some much bigger crayons to hide them. ;-) Art George Hartzell wrote: > Tony Sleep writes: > > [...] > > With all aliasing the easy cure is to degrade the frequency of image > > information so that it falls well within the Nyquist limit. > > Defocussing, or > > antialiasing filters, do the job. I presume software that attempts to > > deal > > with it relies on some sort of blur function, which is how you can > > attempt > > to deal with it in PS. It could be clever and only act on areas where > > aliasing occurs, but there is no way to deal with aliasing and retain > > the > > HF info that causes it. Aliasing is just an inescapable property of > > pixels. > > [...] > > I think that it can make a big difference between whether you degrade > the frequency of the image before/while it's scanned (e.g. defocusing > the scanner) or whether you try to blur in photoshop. > > When you do it as part of the scan, you just have to throw away enough > information to get within the Nyquist limit. > > Once you've collected aliased data though, the problems are usually > much larger blobs and you have to blur the daylights out of them to > get them to go away. You end up throwing away much larger details (is > a large detail like a jumbo shrimp?). > > g. > > Unsubscribe by mail to [EMAIL PROTECTED], with 'unsubscribe filmscanners' or 'unsubscribe filmscanners_digest' (as appropriate) in the message title or body
[filmscanners] Re: Grain aliasing: Thoughts, solutions?
On Fri, 11 Oct 2002 19:28:39 -0700 George Hartzell ([EMAIL PROTECTED]) wrote: > I think that it can make a big difference between whether you degrade > the frequency of the image before/while it's scanned (e.g. defocusing > the scanner) or whether you try to blur in photoshop. > > When you do it as part of the scan, you just have to throw away enough > information to get within the Nyquist limit. Yes, I agree. Trying to deal with an aliased scan is far worse: the errors are 0.5x the frequency of the optical signal which caused them,so much larger. Moreover colour aliasing has introduced a whole new class of problems which simply don't exist if you defocus/filter the optical image upstream. Regards Tony Sleep - http://www.halftone.co.uk Online portfolio & exhibit + film scanner info & comparisons Unsubscribe by mail to [EMAIL PROTECTED], with 'unsubscribe filmscanners' or 'unsubscribe filmscanners_digest' (as appropriate) in the message title or body
