Dust and defects on CCD sensor

Appendix to Dirty Scanner Optics article
Scan from negative

A brand new Minolta Dimage Scan Dual II film scanner produced noticeable streaks due to defective pixels or other irregularities in its CCD sensor (perhaps dust). The yellow arrows point at the most noticeable streaks; especially annoying is the pink line from a "hot pixel" near the top of the image. This was a scan from Kodak Gold ISO 200 negative film.

The owner reported that streaks were noticeable on about 50% of the scanned images, and the scanner stopped producing them after he posted this image with complains.

Scan contributed by Markus Arike.

Vadim Makarov

Reader's Comments

I too have these stripes intermittantly on my Minolta Dimage Scan Dual II. They show as one or two rainbow like stripes across the picture in the scan direction. In my case I don't think it's dust, because it will disappear if I shut down the scanner and the scanner software and restart it. It has made me think that it is due to some kind of software problem and/or interference between the software and the picture and/or a software conflict in the computer. After I started to use VueScan, the problem was absent for a long time, but then reappeared, however not so frequently. I recently upgraded to the latest version of VueScan and have not since had the stripes - and I cross my fingers (in vain?).

By the way, Canon D60 and Nikon D100 now has 6 megapixel sensors, which offers quality almost on par with traditional film scanned on a desktop scanner (drum scans is another matter). If the rapid development continues, in a year or two professional and "prosumer" digital SLRs will produce better pictures than film, and then a lot of us will no longer use film cameras and scanners, except for trips to places without electrical sockets.

-- Leif Olstrup (leifolstrup@hotmail.com), July 3, 2002

Relevant discussion pulled from photo.net


I currently have a HP, multi use printer/scanner/fax (model 710) and it just doesn't do a great job on photo's... documents are fine. On top of not be as sharp as would like, it also streaks the image and no matter how I've tried to clean where I think it is coming from, it does no good...

Attachment: 586x524 image (scan with streaks)

-- George Schwend, July 12, 2001


What's fun the streaks on your image are not exactly vertical. Did you rotate it by small angle in the scanning software?

By the way, you may get exactly the same problem with new film scanners :-(  <here I put a hyperlink to this very page>

-- Vadim Makarov

I get these too sometimes. But it's not consistent. And I get them on both my Epson Perfection 1200 with transparancy adapter, and with my new Minolta Scan Dual II. When they start occuring every scan I do during that "session" has them, sometimes quite bright and prevalent. It is not due to a scratch on the neg as flipping the neg produces the line in the same place now but with the neg flipped. It must be some hardward thing. And the most puzzling thing of all is some days I do not get it at all while other days it's quite bad. And sometimes this with using the same chrome or neg both times! Anyone know what this is and how to control or get rid of it?

Also excerpt from Richard's email to me:

I have a Minolta Dimage Scan Dual II that has this problem. However, it is not consistent which has me thinking it's perhaps dust. However when it does show up it seems to be in the same or similar place (and sometimes one strong well-defined line with a lighter second line parallel). If this is dust is there some way to clean out the CCD sensor myself? One time I blew some air (using a hand bulb air nozzle) in the film slot of the scanner hoping to dislodge some dust, if that was the problem, but the next scan the line seemed darker and deeper! Then the next day and the few days since my scans have been perfect and clean with no signs of those lines! But they will probably be back. By the way, I also had this sometimes with my Epson 1200U flatbed when scanning negs or chromes using the transparency adapter. AGAIN, they were inconsistent with their presence...

-- Richard Sintchak

These streaks are due to dust directly on the CCD, in my experience.
My Acer 2720s, which I can recommend as probably the best value for money in 35mm filmscanners, developed these symptoms, after about 14 months use. I (carefully) dismantled it and cleaned the CCD sensor, and the problem was cured.

I don't recommend that you do this job yourself, though, unless you have experience with dismantling delicate optical and electronic assemblies. Even then, you may put the entire scanner at risk by trying to get access to the CCD surface.
Prevention is better than cure, and keeping a dust cover over the scanner when not in use is a good idea, IMHO.

-- Pete Andrews

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