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View Full Version : New scanner does "banding" in underexposed areas



andre
16-Nov-2014, 11:00
I just got a new scanner, the Epson V800, as an upgrade for my V600.
The V800 seems to have a problem with underexposed areas where vertical banding is visible.
I have scanned the same negs on my old v600 and never had that issue.

I have the problem both with silverfast and Epson Scan.
With or without film holder.
Large negs & small negs.

I have upgraded the driver and software.

It only happens where the negative is very thin and underexposed.

Is this a common problem with scanners?

125133

Kirk Gittings
16-Nov-2014, 11:33
Yes. A negative must be properly exposed even for a scanning workflow. A scanner can't save an under exposed negative, though a good drum scan can pull out anything that is there better than a non professional grade flatbed.

mdarnton
16-Nov-2014, 12:27
Interesting. I remember that photo from your older Flickr pix, so I went to that old one and pumped the contrast up a lot to see if it was there, hidden, with your old scanner, and it really is not. Consequently, I'd call that a scanner defect in your 800, not a defect inherent in flatbeds. Another of yours, the woman with the white blouse, has it, too, as I'm sure you know. I hope that's not what we get with the new 800-series scanners.

If the exposure is right for the neg, on the scanner, I don't know why flatbeds would do this and drums wouldn't, because it implies that ANY flat grey area on a flatbed would do it. The scanner can't know if the neg it's scanning is underexposed. The only unusual thing it would do is that you would need to pump up contrast for underexposed negs, and if that's what's causing it, than any flat neg would reveal this problem when taken to normal contrast, not just thin ones.

The curious thing to me here is the regularity of the bands, which implies some interaction with another regularly-repeating factor. I wonder if you are using a dirty power source for the scanner? Is it the original power brick? Can you try the scanner somewhere else, with a different power source? To me it looks like a power problem.

Jim Noel
16-Nov-2014, 12:34
I have never had such a problem with my Microtek Scanner.

Kirk Gittings
16-Nov-2014, 12:56
You are probably right mdarton. My point, poorly explained I grant and done without much thought, is that if you try to boost detail in an underexposed file (underexposed shadows) you are going to get artifacts. On flatbeds that usually shows up as banding artifacts-very quickly from "non-professional" flatbeds-less so from ones like the IQSmart but they will show up and less so from also from Imacons but they will show up and much less so from good drum scans. I have many years of experience with this from all the various Epson's and Microtek's and IQSmarts and Imacon's. Currently I own an Epson 750 and have access to two Imacon's and an IQSmart. The banding always reflects the direction of travel of the sensor I assume from variations in the sampling somehow. So when I have issues with this it is one of the reason's I go to good drum scan.

andre
16-Nov-2014, 13:37
Thanks a lot Michael! I'll look into that!



The curious thing to me here is the regularity of the bands, which implies some interaction with another regularly-repeating factor. I wonder if you are using a dirty power source for the scanner? Is it the original power brick? Can you try the scanner somewhere else, with a different power source? To me it looks like a power problem.

koraks
16-Nov-2014, 13:48
Most banding of the kind that runs along the length of the carrier direction that I have encountered so far was due to dust or other filth on the calibration area of the scanner. However, in this case, the regular pattern suggests that something else is amiss. Bad filtering of the power source like mdarnton suggests does sound like a candidate. But it could be a dozen other things as well. It does look like a hardware issue.

StoneNYC
17-Nov-2014, 00:52
Guys, it's a V800

Brand new on the market, it wouldn't have an old power spruce.

My guess is this is due to uneven light because of the use of LED's instead of hot lamp illumination in the lid.

koraks
17-Nov-2014, 12:51
Guys, it's a V800

Brand new on the market, it wouldn't have an old power spruce.
Not necessarily. A user may very well replace the scanner and hook it up to an existing power source, possibly kept from a previous device, or even a device that has a lower power requirement than the current scanner, resulting in higher noise due to lack of proper filtration for the required power levels.


My guess is this is due to uneven light because of the use of LED's instead of hot lamp illumination in the lid.
Possibly, but there's nothing inherently uneven about LED light. LED illuminators have been used for years in electrophotography applications with completely reliable and reproducible results. This does not take away possibilities of a defective device, but the even pattern of the banding is quite suspicious. LED failure would typically result in intermittent banding on specific locations, not so much an even banding pattern. This pattern is more suggestive of some for of intereference between two signals; the suggestion of insufficient filtration on a power source mixed with a sampling frequency doesn't sound particularly far-fetched. But, as it is, with the little information we have, your guess is as good as mine.

Jmarmck
17-Nov-2014, 13:08
Just a thought. I had this problem when I did some of my first scans on a V700. It turns out that the film was not positioned correctly. I still will shove that better scanning a little too far and lord only knows what I will get. Bottom line is make sure you have the source properly placed.

Adamphotoman
20-Nov-2014, 08:27
Try making 5 scans over and over again. Do the bands show up in exactly the same place each time? Can the scans be stacked assembled and averaged?
This is one way that random noise can be reduced in difficult scans.
A slightly different approach was used with an Agfa Duoscan. I was able to produce banding in different areas by shoving the holder farther and rescanning. By averaging the banding was less problematic.

axs810
29-Nov-2014, 11:40
Are the two scanner contacts clean? Not sure what the part I'm talking about is exactly called but you'll find them between just above where the scanner closes and the scanner glass. I had some weird errors one time scanning at my old school because those two contacts were dirty. I would also try unplugging and replugging the scanner cables in.

andre
8-Dec-2014, 03:04
Guys, I've not abandoned the thread.
As soon as I fix it will let you know what the reason was!

I can tell that it's not the calibration area, not the cables, not the power source.