Lynn,
No, the light source and the CCD remain stationary while the carrier moves
past. The hot center is along the axis of movement - ie. if you held a paint
brush against the negative and moved the negative horizontally past it you
would end up with a stripe along the negative where the brush wiped. So, the
darker stripes along the edges are not a function of the movement.
I still think the ultimate problem here is in the optics - it just looks too
much like a dispersion or defraction problem. However, I don't think it is
defective (in the broken sense) just inexpensive. And so, we need to learn
how to minimize the effect on those photos that exagerate the problem.
I have hopes of finding out how VS controls the scanner differently and then
being able to make adjustments to the scanning when needed to reduce this.
More to come..
/fn
-----Original Message-----
From: owner-filmscanners@halftone.co.uk
[mailto:owner-filmscanners@halftone.co.uk]On Behalf Of Lynn Allen
Sent: Friday, July 06, 2001 11:19 AM
To: filmscanners@halftone.co.uk
Subject: RE: filmscanners: Stains and Grains (was Yellow Stain)
Frank wrote:
>The light source is a single small light tube (3/16" x 2 1/2" about) and it
>is masked off via a slot so only the center 1 inch or so is used to
>illuminate the film.
So you're saying, Frank, that the light source and the CCD array are
traveling in tandem--do I understand it so far? If this is the case, could
the problem be that the elements are not traversing *far* enough to make a
fully-lighted and/or fully sensed scan? The problem remains: a "hot" center
and a slightly "cooler" periphery, in what would appear to be Kelvins. That
still sounds like a light problem--although I couldn't venture as to exactly
what's happening. And I can't visualize how the sensor array is arranged, or
how far it travels.
I'll admit that I have neither the technical know-how nor the intestinal
fortitude to take my Scanwit apart, so thanks for doing this. It's clear
that the techs at Acer (or anywhere else, for that matter) are not going to
volunteer the information.
Best regards--LRA
>From: "Frank Nichols" <frank@theNichols.net>
>Reply-To: filmscanners@halftone.co.uk
>To: <filmscanners@halftone.co.uk>
>Subject: RE: filmscanners: Stains and Grains (was Yellow Stain)
>Date: Fri, 6 Jul 2001 09:38:01 -0600
>
>Brief update:
>
>I decided to take my Scanwit apart last night to see what the optics look
>like. The design is much simpler than I had imaged. The light source is a
>single small light tube (3/16" x 2 1/2" about) and it is masked off via a
>slot so only the center 1 inch or so is used to illuminate the film. This
>eliminates any "spreading" lenses that I suspected would be the cause of
>the
>yellow stain.
>
>The CCD package appears to be a monolith assembly with integrated focusing
>-
>I dont knowif it can be disassembler, so I left it alone.
>
>This means the problem originates within that CCD assembly - whether in
>optics or electrical I can't say.
>
>Since others have also reported the yellow stain, I am now going to make
>the
>assuption it is inherent in the design and is not a broken unit. Therefore
>I
>will be focusing on ways to correct the stain. Tonight I will post my first
>crude method on the website.
>
>(Jerry, yes I will take a shot at you car picture and send you the results,
>I may need the original - 2700 DPI image. Could you send it to my web site
>if I give you a password?)
>
>/fn
>
>-----Original Message-----
>From: owner-filmscanners@halftone.co.uk
>[mailto:owner-filmscanners@halftone.co.uk]On Behalf Of Oostrom, Jerry
>Sent: Friday, July 06, 2001 12:57 AM
>To: 'filmscanners@halftone.co.uk'
>Subject: RE: filmscanners: Stains and Grains (was Yellow Stain)
>
>
>
>
> > -----Original Message-----
> > From: Alan Tyson [SMTP:AlanTyson@bknowl.freeserve.co.uk]
> > Sent: Friday, July 06, 2001 5:18 AM
> > To: filmscanners@halftone.co.uk
> > Subject: Re: filmscanners: Stains and Grains (was Yellow Stain)
> >
> [Oostrom, Jerry] []
> > So if it's only occasionally a problem, don't worry. You can
> > got a lot of conventional prints made from your negs for the
> > difference in cost between the Scanwit and anything else
> > that's worth having. Some negatives have always been
> > difficult to print. The mistake occurred at the moment the
> > button was pressed, not when the scanner was bought.
> >
> [Oostrom, Jerry] If only it were an occasional problem for me :-(
>
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