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  • Removing Finger Prints

    Hi All!

    I have been working on a several pictures recently that have finger prints embeded into the picture. The pictures are about 70 years old and have black (mold) like finger prints, or on a few white fingerprints.

    I have tried using a dust and scratch filter and then making a snapshot and eleminating the black mold with the history brush. Often it blurs too much and I end up adding noise back in. I have similarily tried using the blur tool and layers set to darken or lighten depending on the dust color. Both methods are a ton of work. I don't mind the clean up but wonder if there is another method that would entail channels to eliminate the black finger prints?

    I've attached one of the photos I am presently working on. I have had to resize it a few time to post. Hopefully it will be large enough for you to see the fingerprints in question.

    Your feedback would be greatly appreciate.
    Attached Files

  • #2
    Try duping the image, using threshold to isolate the prints as much as possible, erasing (or painting in, whichever is appropriate) the non-fingerprint areas.

    Now dupe your image again and apply liberal dust/scratches filter, then nudge up the d/s threshold until the prints just disappear. Don't worry how blurry it looks.

    Now add a layer mask to your newly blurred image, then alt-click on the layer mask to bring it up into your editing window. Now change to the thresholded layer, ctrl-a to 'select all', ctrl-c to 'copy'.

    Now go back to your mask layer. It should simply be a blank white window. Ctrl-v to 'paste', then ctrl-d to 'deselect'. Click on the thumbnail of your blurred image and you should have the mask applied (you may need to invert the mask if it's showing everything but the fingerprints instead of just the fingerprints).

    You can now delete the thresholded layer you copied from, and what you should have left is your original and on top of that a layer consisting of the blurred image masked by the fingerprint.

    This takes some playing with. Sometimes it helps to apply a gaussian blur to the mask. This doesn't solve the problem, but could help minimize it. Use ctrl-a (select all), ctrl-c (copy), then make a new layer and 'paste merged' to have an image you can clean up without damaging your original. Alternatively, you can duplicated your original, turn off your original-original layer, then 'merge visible'.
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    • #3
      Finger Prints

      Thanks Doug.

      I'm already lost trying to follow along. I understand the steps but find using the threshold to isolate the prints pretty hard. I haven't a clue what to set the threshold too. I follow the rest of the steps just fine. Please forgive my ignorance. I do understand the theory of the layered mask. Now, to just get to that point.....

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      • #4
        Threshold only has one function. It makes everything below one brightness level black and everything above white.

        Go to Image>Adjust>Threshold and it should show you a slider. Move it back and forth to see if it isolates the fingerprints. As I said, it will probably pick up a lot more than the fingerprints, but the rest can easily be painted out.

        Plus this won't work 100% of the time. It's best when the marks are signficantly lighter or darker than the surrounding areas.
        Learn by teaching
        Take responsibility for learning

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        • #5
          Finger Prints

          Gotcha, the part I now get is that it will probably pick up a lot more than finger prints....

          I appreciate your suggestion.

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