Imacon 646 horizontal banding

[gmed]

I noticed that on my panoramic scans on velvia, where the sky is bright and not a lot of infomration, the scanner causes horizontal banding which are very faint, hardly noticable, equally spaced. I sent a fff file to tech support and they cant see it. I can see it if I convert it to BW and increase noise. I cleaned the bulb which solved the vertical banding issue. the scanner only has 820 scans, but no service yet. I never notice it on filmls that have a lot going on. only whie empt spaces.

any thoughts?

[onnect17]

Could you post a link to the file to take a look?

[koh303]

Most likely dust on the bulbs.
Remove the outer cover, and then gain access to the bulbs.
Unplug and remove the lower bulb and wipe it down with a nice clean microfiber cloth.
Test again and report back.

[gmed]

Actually I cleaned the bulb which took care of the vertical lines. the horizontal one is along the axis of the ccd, as the lens goes side to side. I belive its due to dust on the lens.

[koh303]

Dust on the lens, like a scratch does not create a visual artifact such as a line. More of a blurred spot and it would have been a major dust particle (several mm across) to create that.
Horizontal banding could be due to improper movement of the drum due to unlubricated pressure rollers, which are also very easy to fix. There were several recent threads about this in the imacon users group on yahoo, though you can just remove them, clean, lube and put back to find out.