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Help: how to isolate/clean green dirt in scan

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  • Help: how to isolate/clean green dirt in scan


    I have another challenge.

    This scanned image has green dirt. The negative was already cleaned with PEC12 cleaner before scanning, but there is still a lot of green mould?

    Is there a way to isolate it fast in Photoshop and clean this up?
    Is it possible to isolate the green color and then use a channel mixer to get rid of the green color through selections?

    I have more of this kind of problem and would appreciate it a lot if someone could advice me how to attack this problem. Much appreciated. Thanks a lot.
    Attached Files

  • #2
    Re: Help: how to isolate/clean green dirt in scan

    If you look in the green channel, there is almost none of the green stain there. Replace the red and blue channels (or portions) with the green channel and you'll be down to the big black stains, which are smaller and should be removable by cloning.


    • #3
      Re: Help: how to isolate/clean green dirt in scan

      Thanks, but I am not sure what you mean. How do i replace the red and blue channel?
      You mean save the green channel as gray rbg, combine the colored original and paint over the stains?
      I would appreciate some given steps to take for the approach you recommend.
      Sorry i am still a photoshop beginner.


      • #4
        Re: Help: how to isolate/clean green dirt in scan

        One approach is to use the Channel Mixer adjustment in photoshop. In the dialog, select the green channel, then use the sliders to get a mix that eliminates the noise. Usually something like red +50%, blue+50%, green -20% would do it. Another approach is to paste either the red or blue channel into the green one. There's a tutorial on that here: If you want to preserve the original colors in the rest of your image, neither of these approaches is very good, but I suppose you could work around that by masking.


        • #5
          Re: Help: how to isolate/clean green dirt in scan

          Well in my opinion, this is a mess. First look at the channels like 3pco recommended and notice that the blue channel is a complete bummer. Copy the layer and use the channel mixer adjustment layer and try the "green filter" option. Set the blending mode of that layer to luminosity and turn off the background layer which gives you a b&w image. Clean that up as best you can and than turn the background layer back on. Place a new 3rd Layer and set the blending mode to color and work on the messed up colors. Thats what I tried and the results after about 15 minutes were not very good but here it is.
          Attached Files


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