Vertical color banding problems

[normis]

First - hello, this is my first post on the forum! I'm a new Silverfast user and hope to learn it well.
I have a problem with scanning images that have large same color backgrounds, like a sky.

I have the Plustek 7600i and the Silverfast 6.6.2 SE. I have a Mac with Snow Leopard all latest updates.

The problem is - it makes some weird vertical banding stripes (I don't know what to call them, zones of different color?). v**s**n with similar settings has no problem in making me a clear sky. I could use v**s**n all the time, but Silverfast somehow gives me sharper pictures (no, sharpen is off in both places).

Here are some samples.

1. Problem with Silverfast. Notice the reddish areas in the sky and on the camper.



2. No problem in v**s**n. Sky is clear. I didn't try to hard to make the overall colors 1:1 the same:



3. Added levels to see the problems more clearly:



4. Again, v**s**n has no problem:



So ... what in Silverfast could cause the weird coloration issues? Any ideas at all?

[LSI_Ketelhohn]

Dear customer,

This is how the scanner delivers the data.
The stripes are visible in SilverFast because we use 48bit colordeapth processing.
Also there are several filters which could increase or decrease such an issue.


kind regards,
Arne Ketelhohn

[normis]

I could not find a filter/adjustment combination that would get rid of the stripes, it really seems as if the scanner would deliver this. The problem is - other software don't have these stripes at all, no matter how many bits are used, or other setting combinations. Would it be possible that Silverfast includes a driver for Plustek 7600 that has a problem with interpreting the driver, and that the other software has it's own driver?

Can I help debug this issue in any way? I have images where the problem is much more severe

[LSI_Ketelhohn]

We are using the standard manufacturer's drivers installed in the system.

It is possible other software has active filters reducing the effect with an un-sharpening mask.
For SilverFast this has to be activated in the "Filter" drop down as SilverFast only alters the image when told to do so by the user.

kind regards,
Arne Ketelhohn.

[normis]

I cleared all the settings, even reinstalled Silverfast from the original disk, with no upgrades applied. Changing any possible settings doesn't change the fact, that there are very disturbing stripes over the image. All films show this. The rest of the scanning software also uses the same drivers, and their settings have also been changed to any other combination. Such stripes have not been seen even once in other programs. Only in Silverfast.

USM doesn't do anything to color and you know it. I know very well how it works, but just for the sake of argument, I experimented with it too.

Here is another scan with increased contrast, so you can see the stripes better:


Basically you are telling me that this is normal, and that I should use some other program. I can't accept this as a solution. I can offer you any kind of information you want, get me in touch with the experts in the development team, give me a debug mode, whatever. I know imaging software and computers at a very high level and I can help you solve this issue. Just give me something !

[LSI_Ketelhohn]

I am not saying this is normal.
Only that other programs do not see this error because their color bit depth is not high enough or they suppress the error by altering the image.
You should contact the manufacturer about this.
Software sided this could only be solved by color filters or unsharpening the image so much that you lose image content.

kind regards,
Arne Ketelhohn.

P.S.: sorry about the delay.

[michelh]

I am having the same problem as normis and I notice other posts complaining about the same problem.

I have the Plustek 7600i and I am scanning transparencies with the film still in the slide frames. I have rotated the same slide in the scanner and I do notice that the banding occurs on the same side of the scanner. Sometimes the banding does not happen.

Like normis, I have tried various combinations of settings. What settings do you suggest?

However, the other posts mention banding problems with other brands of scanners and so this suggests it is not a scanner problem. That means it is a software problem either in SilverFast or in the drivers it uses.

Do you think it is a scanner problem or a software problem?

Plustek online help is not as good as SilverFast and so I am not expecting much advice from Plustek on this matter.

I use Silverfast 6.6.2 SE.

[LSI_Ketelhohn]

The above images most likely display a scanner issue.
SilverFast has no Filter or function to produce something like that.

kind regards,
Arne Ketelhohn.

[degrub]

Are the lines parallel to the scan motion or orthogonal to it ?

If parallel, could have a sensor issue (dust in the light path for example or in the calibration area)

if orthogonal, then the fluorescent light source may not fully warmed up - usually 20 minutes or more, longer for older tube.

Or the power supply may not be steady enough - try plugging into a UPS with voltage regulation (AVR), Or the self calibration has issues.

Try a raw scan in both programs and open in PS, apply a gamma curve and see what you get.

What color spaces are being used in the two programs ?

BTW, the white point and color balance looks to be different between the two. Check the individual RGB channels. Check for color cast removal settings. i can see the same banding in the VS version of the 1st set of images, just much lighter. i'm viewing them on a wide gamut monitor so it may exaggerate the effect some and make it more visible.

Just some ideas from previous experience,

Cheers!

[normis]

The lines are visible in the image above, they are perpendicular to the scanning element (ie they are parallel to the sensor I guess).

Apparently the problem was in the drivers, I installed Parallels virtual machine, and installed the drivers and Silverfast all for the Windows XP in the virtual machine. No lines, no problems. At the same time, I can switch back to MacOS and still have the lines in the scans, so the drivers have some issue. Plustek site lists no drivers at all for this model, so I have no idea what to do now. Keep scanning in Windows? Plustek doesn't answer emails.

[normis]

sorry, mistake. just looked at the scanner and realized the sensor runs in the direction from top to bottom of the image. so the lines run in the same direction of the moving element.

[normis]

Problem was solved by Plustek, they released new drivers for MacOS. Vertical color stripes are gone after applying the patch from their webpage.