[sane-devel] Fwd: HP scanjet IIcx /t resolution

George Georgalis George Georgalis <georgalis@gmail.com>
Mon, 6 Sep 2004 11:47:05 -0400

On Mon, 6 Sep 2004 15:22:42 +0100, Martin Collins <martin@mkcollins.org> wrote:
> On Sat, 4 Sep 2004 18:21:11 -0400
> George Georgalis <georgalis@gmail.com> wrote:
> > It's spec says 600 dpi but somewhere between 300 and 400 dpi it
> > starts to do double passes (exactly when it starts depends on the
> > image). I think I understand what's happening, though I don't know
> > the vocabulary to explain it (software gets a higher resolution than
> > the optical quality requiring multiple passes).
> You are thinking of "software interpolation". That's not it though.
> I would call this behaviour "backtracking" and like Abel says it is
> probably due to a bottleneck in the data path.
> Are you using the SCSI card that came with the scanner? Does it have
> a serial-port style connector or a proper SCSI connector?
> If the former this is probably the problem. Getting a proper SCSI card
> will fix it. I recommend Iwill as good value for money.

Thanks for both responses -- makes sense, not  interpolation but,
channel bandwidth.
Seems I was scanning different widths when scanning different images.

But I still find this odd as I have scsi-2 controller, (Buslogic
FlashPoint) connected to the older "scsi-1" scanner. It's unfortunate
and strange that the scanner is faster than the the bus on it...

More importantly it I've not been able to set the bit depth to greater
than 8, I think the scanner is rated to 16. There have been times I've
adjusted xsane settings when the bit depth has gone to 1, and even
restoring the old settings will not make 8 bit depth available again,
I have to fix the setting and restart it.

In the viewer console it says "1 bit/color, 3 colors"  ...I'm don't
think the image is more than 8 bit but I think is is that many. So I
seem stuck with 256 colors, what could be wrong? (BTW - this box has
1Gb memory)

// George

George Georgalis, systems architect, administrator Linux BSD IXOYE
http://galis.org/george/ cell:646-331-2027 mailto:george@galis.org