Re: filmscanners: My replacement 8000 is banding like the first one :-(

[Isaac Crawford <isaac@visi.net>]

Stephen Kogge wrote:
> 
>         Re the "banding problem"
> 
>         My first reaction was that the scan is being done "off" a native
> resolution 4000 dpi, 2000 dpi, 1333.333 dpi, 1000dpi etc and that software
> interpolation was/is being done.
> 
>         After a few of the other comments about possible mechanical
> problems I remember watching either my AT210 (flatbed) or an HP
> doing it's "scan dance" where it scans forward, pauses while the
> programed IO SCSI interface dumps the scan buffer, backs up past
> the backlash of the gears then scans forward for another chunk.
> A lot of the early scanners had poor SCSI performance.
> 
>         Does the scanner seem to stop and start or is it a smooth scan?

        This is completely out of left field, but could it be a power supply
(in the scanner) issue? Someone else commented on how this only seems to
show up with scanners using stepper motors... Could the stepper motors
cause spikes in the PSU that could interfere with the imaging side of
things? Either sending noise to the CCD, or even pulsing the light
source are a couple of possible ramifications... Just a wild guess...

Isaac