S. Matthew Prastein wrote:
>No, I do not scan 16 times, only 3, but at
>highest resolution.
That would be the "high 32" in Mira, or 48-bit in Vuescan. I'm not sure this
buys you much with thin negs, but OTOH every little bit helps (pun not
intended). :-)
>I _think_ I see improvement in noise levels
>then, but I can't convince myself that doing more than 3 scans buys me
>anything. But Ed Hamrick _seemed_ to be saying in his last
>communication that even three scans is overkill, which seems to
>contradict earlier statements that multiple scans were good stuff at
>highest resolution, but inferior, if only lower resolution was
>needed/desired, to single scans at high resolution combined with
>compaction to lower resolution.
Hmmm. I'd say it depends on the level of "noise." I've done up to 10 in
desperate measures, but it's pretty hard to quantify how much good multiples
beyond 4 scans do--see above. :-) Variable exposure would be much handier,
but Acer doesn't have it.
One area you can play around with, in either Mira or Vuescan, is the film
types. AFAIK, this is a software "filter" of the raw scan in both programs,
but it "can" give you a better start-point for IP correcting. As you know
(or will soon find out), when Mira outputs a "raw" negative scan, it's
exactly that--in the negative with no film-mask. Reversing it in Photoshop
and applying Auto Levels works pretty well, though. Vuescan outputs the raw
scan in positive.
>On the ScanWit 2740S, using ICE and specifying 3 scans actually
>results in 6 scans, presumably 3 IR + 3 visual. Also, ICE or not, I
>must set focus to Preview Only; if set to focus on both Preview and
>Scan, I loose registration and the scan data is useless.
That's somthing I haven't run into, but it could happen.
Anyway, good luck and enjoy. Scanning and correcting underexposed negs can
be a PITA, but it *does* build character. ;-)
Best regards--LRA
>On Fri, 20 Jul 2001 22:31:01 +0000, you wrote:
>
> >>I seem to be missing something. I have an Acer Scanwit 2740S, which
> >>requires multiple passes to do a multiple scan. I thought that this
> >>was the right thing to do to get lower noise when scanning at 16x. so
> >>as to be able to average the input from successive reads. And, I
> >>thought this would help in extracting info from seriously underexposed
> >>negatives. Am I all wet on this?
> >
> >IMHO, yes (no offense intended--you said it first). :-) I have an Acer,
>but
> >without the IR (it's a 2720S). First of all (I haven't been following
>this
> >thread), are you saying you're making 16 passes on underexposed negs? 2-4
> >should be more than adequate. I'd start with 1. I also don't know what
>you
> >mean by "seriously underexposed." 1 stop? two? three? These are going to
>be
> >thin, but I've gotten credible results from "very" thin negs (pushed
>TriX,
> >and 4 stops under) with the Acer (I used some tricks). Multiple passes
>are
> >more likely to help noise problems in dense negs and slides (I could be
> >wrong on this, of course--but dense is where most of my problems come
>from)
> >
> >If the film detail isn't there, it isn't there. You know that, of course.
>To
> >"suck" the most out of it, I think you need to play with the Levels and
>the
> >Curves in Photoshop (or your favorite IP). Noise may in fact be a serious
> >problem--reduce it as much as you can in Mira or Vuescan, then try to
> >correct in your IP. You may need to scan at several different settings.
> >
> >If you haven't checked out Pete's website (Photoscientia whatever), do
>so.
> >It's an excellent guide to the Scanwit (Pete didn't like the beta 2740s,
>be
> >advised--that doesn't make it 'bad,' it's just drawn that way :-) ).
> >
> >I don't know that I've helped, but feel free to contact me if you have
> >questions.
> >
> >Best regards--LRA
> >
> >>
> >>On Fri, 20 Jul 2001 11:42:23 EDT, you wrote:
> >>
> >>
> >> >You should _never_ need to do the 16x scan pass more than
> >> >once. The preview is done in one pass (at low resolution), and
> >> >will be used to compute the optimal CCD exposure and cropping.
> >> >
> >> >All other things can be re-done by pressing the "Scan mem."
> >> >button, making it unnecessary to _ever_ scan the same piece
> >> >of film twice. If you're a belt-and-suspenders person, make
> >> >sure the raw scan file is written to disk as well by using
> >> >the "Files|Output raw file" option.
> >> >
> >> >Regards,
> >> >Ed Hamrick
> >>
> >>--
> >>Matt Prastein
> >>
> >
> >
> >_________________________________________________________________
> >Get your FREE download of MSN Explorer at
>
>
>--
>Matt Prastein
>
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