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Recommendations for Scanning Slides

Started Aug 7, 2021 | Discussions thread
OP paul wassermann Senior Member • Posts: 2,274
Re: Dust removal without an NIR image

ProfHankD wrote:

iljitsch wrote:

I used an Epson scanner with slide and negative scanning attachments to scan slides and negatives. Took a good amount of time, but now I have digital copies of all my slides and negatives.

Biggest issue: dust and other debris. I understand that this can be largely fixed in software for color film/slides if you have a scanner that has an infrared channel. So I'd highly recommend that.

Flatbed scanners tend to have more of a dust issue than other methods of slide scanning -- after all, they have a piece of glass fixed horizontally near the focus plane and it can get dusty.

The dust/srcatch removal is generally done by capturing an NIR image to use as a mask. The dark pixels in NIR are simply interpolated over. A better fix would be to do true inpainting to fill the gaps. I was thinking I could write code to automatically recognize and fix the dust spots without NIR, but it's been done: Automatic Sensor Dust Removal . Yes, that's essentially the same problem as dust on scanned film. Anyway, they link to python OpenCV code that finds the spots & inpaints to remove 'em: Python-Automatic-Sensor-Dust-Removal .

I was able to digitize all my slides by photographing them with my Sony 90mm macro lens using a backlit drawing tablet.  I used masking tape to make a top and bottom little ledge that would hold the slide.  Blew compressed air on the slides and wiped with microfiber cloth and then photographed.  They came out great...surprised how much detail was present in the underexposed areas of the slides.

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