[filmscanners] Re: Raw files in Vuescan

["Myles" <dryden@mgt.gla.ac.uk>]

Date sent:              Wed, 25 Aug 2004 11:13:02 -0700
Send reply to:          filmscanners@halftone.co.uk
From:                   "Ed Lusby" <elusby@adelphia.net>
To:                     dryden@mgt.gla.ac.uk
Subject:                [filmscanners] Re: Raw files in Vuescan

>
> I believe incorrect cropping can lead to autoexposure problems. If there is
> a significant area of black, for example, vuescan would tend to overexpose
> the raw scan, resulting in clipped highlights. You might check your scans
> for clipped highlights. If it's a small enough black area, it won't be
> significant perhaps. Light areas around the actual picture area would be
> expected to cause a loss of detail in the shadows.
>
> Auto cropping remains to be a problem in vuescan. The problem seems to vary
> with scanner and certainly vuescan version, as Ed has made many recent
> attempts to improve auto cropping lately.  However, vuescan 8.0.4 remains
> the best version for me in terms of auto cropping with the LS5000.  When Ed
> changed the auto crop algorithm in 8.0.8 and 8.0.9, he improved filmstrip
> auto cropping significantly, which was his goal. However slide scanning
> autocropping was quite bad. In version 8.0.11 (or thereabouts) he made
> slide auto cropping better, but still not as good as 8.0.4.  One can deal
> with this situation in a couple of ways. You can either install the version
> best for your usage on a particular day, or you can try the various
> cropping options.
>
> When scanning film strips, you should trim the leading edges of the strips
> to be the same distance from the picture area for a scanner like the
> LS5000, which feeds in the bare strip.  I much prefer the Minolta 5400 and
> vuescan for film strips. The auto cropping is very good, perhaps because of
> the use of a film strip cassette holder in this scanner.
>
> Ed Lusby

I have just been looking at your post again and also those which
replied  with:
                        Re: Autocropping (Was: Raw files in Vuescan)

These were all  very interesting and useful to me but I think my main
question was not actually answered .(Much of the discussion centred
on the effectiveness of Vuescan's autocrop feature) .

I was scanning a big number of film strips with Vuescan and found a
few of the output files had black borders (possibly from varied
spacing between frames) .The Raw files,scanned at the same time,
also had borders.

My understanding of Vuescan is that raw files' colors are not affected,
so that I simply have to trim them and process further ( in Vuescan
and/or Photoshop). But the jpg and tif(non raw) output files will already
have their colours adjusted ,somewhat inaccurately because of the
black borders.
Is this a correct interpretation ?

If it is correct then it seems to me working with the raw files is the
preferred next step.

I would appreciate being enlightened on this.
Thanks

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