Re: filmscanners: Autoexposure problem in Vuescan

["Maris V. Lidaka, Sr." <mlidaka@ameritech.net>]

Similar to what you've tried, check the "Advanced Workflow Suggestions" in
the Help file to determine the fixed exposure setting for the film - maybe
that will help.

I assume you've already tried the "None" setting for Color balance.

Have you tried changing the Gamma and Image brightness settings?

The graininess you end up with is a mystery to me, though.

Maris

----- Original Message -----
From: "Rob Geraghty" <harper@wordweb.com>
To: <filmscanners@halftone.co.uk>
Sent: Wednesday, September 19, 2001 6:46 AM
Subject: filmscanners: Autoexposure problem in Vuescan


| I've been scanning some airshow photos and getting the right exposure out
of
| vuescan has been extremely difficult.  The day was very overcast, and
| there's a lot of photos where most of the frame is clouds with some very
| small aircraft.  Vuescan seems to be using an autoexposure algorithm
similar
| to autolevels, but whatever the reason I end up with highlighted grain and
| excessive contrast.
|
| The most frustrating thing is that the preview image looks fine, but I
can't
| find a setting which makes the final image look anything like the preview.
| Please refer to the attached jpeg for a comparison.  The jpeg is small but
| it's big enough to see the huge difference between the preview and the
final
| image.  It's NOT just the cropping process which is the problem here -
it's
| the scanning exposure as well.  I've tried scanning from the raw file and
I
| can't get a good result with the data that has been scanned.
|
| The only workaround I've found is to deliberately include part of the film
| mask in the scan.  This presumably gives vuescan a "true black" to work
| from.  If you crop back to just the sky, vuescan seems to try to expand
the
| grey values too much and you end up with an awful result.
|
| I'm sure by juggling manual exposure values manual black and white points
| etc it would be possible to get a good result, but I just don't have time
to
| do that for every frame.  I've tried white balance, neutral, etc but it's
| all to no avail because the exposure was wrong before it got to the
cropping
| stage.
|
| Any suggestions?  ISTM the only option is to do a preview which includes
the
| film mask, then switch to manual exposure, and keep that setting for the
| rest of the film (or at least the strip).
|
| Rob
|
|