Hi Frank,
OK, then that would mean that the sensor array is vertical to the line of
travel, and the scan is horizontal, as we thought, and that makes sense. Now
optics *could* cause light drop-off, but frankly I don't quite understand
how that mechanism works, either. I'd almost have to see it--and
conemplating that, what I *see* is a part or two left over after I've
re-assembled my Scanwit! ;-) (I actually *did* that with an electric
typewriter, once. For some reason, it still worked! :-))
Best regards, and keep us plugged in--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 12:59:52 -0600
>
>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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