how to fix moire?

Minolta scanners, scanner support and replacement choices
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pakodominguez
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how to fix moire?

Unread postby pakodominguez » Thu Jun 04, 2009 3:16 am

I was in a film mood latelly, and now I just install my old and trusty Quickscan 35. And I find myself deling with Moire: any tips of how reduce or eliminate Moire during the post processing (Photoshop)?
Thanks!

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Re: how to fix moire?

Unread postby 01af » Thu Jun 04, 2009 9:40 am

There are several methods to deal with moiré. Some try to avoid moiré in the first place, others try to remove it after the fact.

To avoid moiré, you may increase or decrease the scan resolution, or you may very slightly de-focus the scan lens (and then restore sharpness in post-processing), or you may sandwich the film with a piece of plastic wrap and then scan that.

To remove moiré, you may experiment with (local or global) desaturation, blur filters, and/or noise-reduction filters. A fairly sopisticated method---which can work wonders in some cases and then hardly at all in others---removes the offending patterns in the frequency domain after a fast Fourier transformation. See here for details.

-- Olaf

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Re: how to fix moire?

Unread postby pakodominguez » Sat Jun 13, 2009 1:08 am

Thanks Olaf,
Alas, the Quickscann doesn't scan BW properly, so I'm shopping for another scanner, preferentially with ICE or a similar technology. In other hand, I want to scan Slides and negatives from the Hasselblad XPan and I'll need a scanner that support panoramic film, or medium format...
Regards

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Re: how to fix moire?

Unread postby bfitzgerald » Sat Jun 13, 2009 10:29 am

You can't use ICE or IR dust removal on "real" b&w film, only the C41 stuff XP2, CN400 etc.
ICE does not work properly on Kodachrome either..IR -SRD does, least on my one.

If you want larger formats you have to really look at the flatbed ones V700/V750 etc, maybe even the V500.. Used the V700...they do well for MF and larger scans, but not as good for 35mm..other scanners can do better.

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Re: how to fix moire?

Unread postby pakodominguez » Sat Jun 13, 2009 6:09 pm

bfitzgerald wrote:You can't use ICE or IR dust removal on "real" b&w film, only the C41 stuff XP2, CN400 etc.
ICE does not work properly on Kodachrome either..IR -SRD does, least on my one.

If you want larger formats you have to really look at the flatbed ones V700/V750 etc, maybe even the V500.. Used the V700...they do well for MF and larger scans, but not as good for 35mm..other scanners can do better.


I know about ICE on BW film (ICE "thinks" grain is dust...), but I don't have only BW neg to scan ;-)
I tried a couple og faltbed scanners but never like quality on those ones for slides or negatives.
I do duplicae slides with the A700 and the 50mm Macro, I have to give it a try for negatives too...

Thanks

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Re: how to fix moire?

Unread postby bfitzgerald » Sun Jun 14, 2009 11:03 am

Depends what you are doing output wise. I still use film, so really a dedicated scanner is the best option for me.
The old slap it on the camera can do some ok results, but won't match a proper scan. And most mini labs do frankly terrible over contrasty auto level adjusted scans, it's a complete waste for time for the serious film user.

I am happy enough with the Plustek I got 7200i, takes a while to get into the scanning workflow, but I am very happy results wise, and to print (which is obviously the goal for me) That's 35mm only though...

I mentioned about the ICE and b&w negs..but you said the scanner you have doesn't do b&w properly..maybe I read that wrong! :o
If you want to do larger formats, then you don't have a lot of choices, bar the flatbeds, unless you want to outlay some serious cash for a top line Nikon scanner

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Re: how to fix moire?

Unread postby pakodominguez » Sun Jun 14, 2009 1:20 pm

bfitzgerald wrote:Depends what you are doing output wise. I still use film, so really a dedicated scanner is the best option for me.
The old slap it on the camera can do some ok results, but won't match a proper scan. And most mini labs do frankly terrible over contrasty auto level adjusted scans, it's a complete waste for time for the serious film user.

Reproducing slides the old way, with the proper lens (in my case, the Minolta 50mm 2.8) is perfect /if/ the slide is properly exposed. Next time you visit NYC I'll show you some 20*30 inches I have on here...

Minilabs' scan can be good for up to 12*18 inches print or even more /if/ the operator knows how to get the best of the equipment. Alas, the most of the times it isn't the case -we were looking for a couple of "printers" (technitians with color correction skills) at the photolab and we got some people from Ritz, with I don't know how many years of experience... well: they don't know how to color correct because the most of the time they sent their work on automatic, while we do manually color correct every single print (unless the customer ask for no corrections). Even if this is "industrial" kind of work it is not a factory: we need artisans, not unskilled labourers!

bfitzgerald wrote:I am happy enough with the Plustek I got 7200i, takes a while to get into the scanning workflow, but I am very happy results wise, and to print (which is obviously the goal for me) That's 35mm only though...

My first film scann was the Minolta Quickscan 35+, that was good at the time. But it scan B&W on grayscale only. Then, the moire issue...
I got 6 years ago a Minolta Scan Multi (up to 6*9) good for the XPan panoramas, but a little slow and no ROC or ICE. This one do it better with B&W

bfitzgerald wrote:I mentioned about the ICE and b&w negs..but you said the scanner you have doesn't do b&w properly..maybe I read that wrong! :o
If you want to do larger formats, then you don't have a lot of choices, bar the flatbeds, unless you want to outlay some serious cash for a top line Nikon scanner

I don't think I'll buy a brand new scaner. I need a faster way to scan the panoramas and I'm shopping for an old HP Photosmart that can do the job for about 50 US$, but again: no ICE...

Regards


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