How can I recalibrate my ScanJet 8250?

[c***@gmail.com]

The user's manual that came with my ScanJet 8250 says nothing about
calibration. It's certainly possible that it does it automatically at
some point of its own choosing, but I would be happier if I could tell
it that "now" is the time. Does anyone know how to make this happen?

And on a related topic, any ideas where I can get my hands on a
service manual for this scanner? The hp site doesn't offer one.

Thanks,
Chris

[Billy Boy]

Not sure but most manufactures have manuals on their web site. Might try that.

Post by c***@gmail.com
The user's manual that came with my ScanJet 8250 says nothing about
calibration. It's certainly possible that it does it automatically at
some point of its own choosing, but I would be happier if I could tell
it that "now" is the time. Does anyone know how to make this happen?
And on a related topic, any ideas where I can get my hands on a
service manual for this scanner? The hp site doesn't offer one.
Thanks,
Chris

[Nigel Feltham]

Post by Billy Boy
Not sure but most manufactures have manuals on their web site. Might try that.

Post by c***@gmail.com
The user's manual that came with my ScanJet 8250 says nothing about
calibration. It's certainly possible that it does it automatically at
some point of its own choosing, but I would be happier if I could tell
it that "now" is the time. Does anyone know how to make this happen?
And on a related topic, any ideas where I can get my hands on a
service manual for this scanner? The hp site doesn't offer one.
Thanks,
Chris

Most scanners automatically recalibrate (for brightness and colour balance)
every time they're asked to do a scan as brightness of the Cold cathode
tubes can vary slightly each time they're turned on (LED scanners also
calibrate to check the image sensor) - inside the casing at the head park
position (or between park and the glass) there is a white strip that the
scanner uses for calibration.

If the white strip ever gets dirty then you'll get odd colour casts on the
image (the scanner rebalances sensor levels to read the dirt as white).

If you have any thin lines of wrong colour down the scan then this is more
likely to be a speck of dust on the optics.