Banding in Skies on Imacon scanner

[Chester McCheeserton]

has anyone experienced this problem and figured out a solution? I'm scanning 5x7 negatives on an imacon scanner (not sure of model, not X1 or X5 though).

I'm getting banding/ uneven densities in sky areas. At first I though it was flare from the code notch, and tried flipping the neg 180 and re-scanning but as you can see from my examples (same negative) the problem simply moves, and not in a constant way. - which leads me to think it's not dust on the sensor.

The negs are slightly overexposed, but nothing very extreme. I am also seeing the problem in sky areas of scan from 6x8 cm neg - different holder - will post example below. The problem only shows up in subtle sky areas. I've darkened and added contrast to make the issue more visible on the jpegs.

Thank you in advance.

[Chester McCheeserton]

similar issue from 6x8 cm neg. the dust and scratches I'm fine with dealing with - it's the straight blurry lines of density that are very difficult to make disappear and look perfect on a large print.

[interneg]

I've seen similar behaviour - usually towards the end of an intensive day of scanning on an X5 that was needing serviced. I think it had to do with the CCD overheating or similar (switching it off & leaving it for a while generally made it go away) - other possible causes are a blob of dust on the sensor, or misalignments within the scanner array - if it persists I'd contact the relevant service people.

[Kirk Gittings]

Make sure it's not in the processing first. I have seen the same thing on transparencies that were processed in a roller transport commercial processor. I too thought it was the Imacon scanner and had it serviced..........

[dave_whatever]

Could just be dust on the lamp or something lie that - might be worth opening up the scanner and giving things a clean - I think they are fairly easy and robust for getting in and cleaning etc. The side panels come off.

[EdSawyer]

What roller transport develops 5x7 sheet film?

Make sure it's not in the processing first. I have seen the same thing on transparencies that were processed in a roller transport commercial processor. I too thought it was the Imacon scanner and had it serviced..........

[Kirk Gittings]

Many of them them, Few labs still run them as they are not made any more AFAIK except for small roll film, But previously companies like Creo's big ones (and another I can't remember the name) could run two 8x10s even side by side.. Do you know what I mean by roller transport? They used to be quite common in pro labs. A lab here ran them for 20 years but eventually went over to an automated dip and dunk for E-6 but continued to run C-41 till they shut down. Most labs now run Refrema dip and dunk like Praus. But I have had streaking even from dip and dunk too recently it seems.

Actually I just checked the lab that ran the streaked C-41 assuming they still ran a roller transport machine where streaking was a known problem-foaming in the developer if I remember right. They actually run a Refrema D&D though-now at least. I assumed that a dip and dunk line would not create streaking but in this case it didmit seems. Unfortunately I didn't scan the film for a couple of years after I had it processed so any ability to track the problem with the lab was lost.

[robert lyons]

I own a 949 and had similar problems in b/w...it went for service and the problem was still there ...so here is what seems to be needed to fix:
be sure no dust on the lamp or ccd
the belts that are used may need replacement..if it has not been used in a regularly they can develop a "flat" spot
their is a prism part to the units that can also have scratches on it and these show up as an uneven long line....this will only become a problem with large areas of mid-tone(i.e. Skies etc.)
I had to have my unit to Hasselblad twice in a 6 week period for all the problems to be repaired correctly...

[Kirk Gittings]

I had to have my unit to Hasselblad twice in a 6 week period for all the problems to be repaired correctly...

Jeez what a PITA. In my case mentioned above, it is the school's Imacon, I convinced them that the scanner need to be serviced only to find out it was the processing of the color neg. Despite student use (you know what I mean) this Imacon is a workhorse that requires little maintenance.

[dave_whatever]

the belts that are used may need replacement..if it has not been used in a regularly they can develop a "flat" spot

Belt issues you'd expect to cause lines running parallel to the short side of a 5x7", whereas dust on lamp or sensor or elsewhere in the optical path you'd expect lines parallel to the long edge.