Improving a homemade scanned slide

Software darktable
1

Hi community,

During this lockdown I’m scanning my slide collection of my travels with a not too good scanner, I know, But so far it’s enough to get an idea of it.

And I’ve found two weird effects of this poor scanning that I would like to solve with dakktable if possible.

I think you can see it in this picture

Ejemplo scan by Alemi Photo, en Flickr

There is an thin red line near the right side, that I’ve tried to eliminate with the “remove color frame” or similar (I have it in Spanish), but I just change the red line to a white one. The other way is to reduce the size so that it leaves out of the picture the red line.

The other is the colour distorsion line in the middle. Any suggestion? I’ve tried with soften and a mask, but it’s not a perfect solution

I would appreciate any suggestion.

Thank you

2

Retouch module would be an opportunity.

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3

The red line to the right is due to a hot pixel in the R-channel CCD. There is nothing to fix it but interpolating from the neighbouring pixels across it.

The faint stripes at left and center might be due to bad dark subtraction, which is temperature sensitive. I see this in my scanner, too. So the calibration obtained just after turning it on when the scanner is cold might not be appropriate after the scanner has warmed up. Thus a new calibration in the warmed-up state might help. So try turning the scanner off after a few dummy scans and then on again, which initiates a new calibration in the warm state. Perhaps this helps.

Hermann-Josef

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