Filmscanner-Forum

Hi!

I am currently testing a Reflecta RPS 7200 for purpose of scanning my photos. The attached example shows the problem: whenever I use multi-pass or multi-exposure scanning, the individual images are strongly misaligned. I use VueScan as a software, but do not think that this problem is software-related. I realized that the scanner first scans from top to bottom, and then the second pass from bottom to top - this may be one reason for the gap (if the scanner always came from the same direction, this may alleviate the issue).

I have already contacted Reflecta, and they suggest me to send the scanner back to the shop and ask for a replacement, because they say it can't be recalibrated by software.
My point now is that I have read from others that multi exposure or multi pass always tends to misalign a bit (see the previous feed, e.g.), which can be seen at the pixel level. Besides this enormous problem here, I am quite happy with the scanner. And since it is meant as a replacement for my old ProScan 7200 (which has a huge issue, and is out of warranty), I am a bit shy to ask for a replacement that may have another issue...

What do You think?

Anybody ever seen something like this?

Best regards,
Björn

Hello Björn,

this is both a software and a hardware problem: Hardware, because reflecta-scanners do not work mechanically that exact as to have two successive align perfectly. It is a software issue, because VueScan does not align the two images -- SilverFast does. I have seen similar ghost images with my DigitDia and VueScan but the offset was not that large. I asked E.H. about this and he responded "Unfortunately, VueScan doesn't work well with low-quality scanners like the DigitDia scanners that don't accurately reposition to the start of the scan".

I would assume that your problem has the same reason.

You can test this by taking two identical scans without touching the target. Then subtract the two images from one another (e.g. with imageJ) and see what you get. The only question to reflecta I can see is, whether this huge offset is beyond specs.

Regards

Hermann-Josef

Hi, Hermann!

Thanks for the quick reply!

Interesting. I have heard about SilverFast doing pixel-based alignment in a previous post, that's true. But I have to say that using my other scanner (ProScan 7200 - which, unfortunately, has an issue with charging of the CCD), I have never stumbled upon any alignment issues with multi-exposure... not with VueScan, and not with SilverFast either. But it is very possible that I have never looked closely enough, since I had to get other issues out of my way - I concede that.

That being said, I did as You suggested and created a difference image from two scans of the same image with Photoshop, see attached. This difference image shows the exact same issues that also my other scan using multi-exposure had (which I sent out this morning). So, I am starting to believe what the Reflecta service said (that it is a true hardware issue).

I have ordered a replacement for this defective item, and will tell You guys how that product performs.
And possibly, I will then really begin to start worrying about the details of pixel-level misalignment...

Thanks again - and: enjoy the weekend!
Best,
Björn