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  • channels

    I've attached a photo that I'd like to ask for some direction on and I'm sure there are plenty that can offer that here! I've used channels only in a very limited way so far and that would be in converting a scan of a photo to black and white using the channel mixer in PS to minimize the channels with the worst of the problems.

    This one, however, I'm dealing with color and I know that when I look at the channels for this attached photo individually, a great deal of the problems seem to be located in the red channel (spots) and the blue channel (stain on the arm, blotches on the skin). The green channel seems the "cleanest". So how do I take this information and go from here to address these issues and get a good start on this photo before getting down to the details? Thanks in advance!

    Attached Files

  • #2
    Hi Gina,
    Here is an example of an advanced use of channels to repair this image.
    I opened the image and also created a duplicate of it with PS Image>Duplicate.
    I converted the copy from RGB to LAB mode. You will see that the damage is in all channels.
    So from here the first thing I did was apply a Gaussian Blur to both the A and B channels (a value of 9 in each). The L channel was in bad shape but I knew from examining the RGB image that the Green channel was much better than the other. So the next move was to replace the L channel in the LAB image with the Green channel of the RGB image. To do this I clicked on the L channel in the Palette to select it only then went Image>Apply Image. From the pull down menu select the RGB image , the Green Channel and set the blend mode to Normal. YourLAB image now looks somewhat cleaner than the original. Next I converted the LAB image back to RGB.
    The next step was to apply a strong Levels shift. I set the Black point on the lady's top button and white point to the blown out area just above her head.
    Next, PS Filter>Noise>Dust and Scratches set to a value of 3 eliminated a bunch of those nasty little spots. You can touch up the image from there.
    Small thumbnail attached to this message and a larger version at the link below.
    Regards, Murray
    Attached Files


    • #3
      hi gina,

      i think you may be getting overly complicated here by going to channels. then again, i dont have ps and i know they do things differently. nonetheless, all i did was channl mixer and contrast/brightness and that's it. mostly, it just needs some blue.

      the rest you simply clean up with clone, heal, or those type tools.

      now, there are some other things you could do to get some pop, but the simplicity is just channel mixer and clean up.

      Attached Files


      • #4
        Thanks Murray for the step by step process. I've gone through it myself per your instructions - first I've tried stepping into LAB mode and your specific instructions kept things clear. The only thing I didn't do was the blurring as I tend to not like doing an overall blur on a photo, but rather use it selectively if absolutely necessary. I did see some improvement with your method and I can see from this point I'd need to just start with the more delicate cloning and healing.

        Craig, you could be right about over-complicating. I've seen some great results here from people doing things with the channels and other color spaces and thought this would be as good a point as any to step out and start exploring since some of the damage does seem more evident in specific channels. Even so, I will likely end up back where I started with my trusty cloning tool!

        Thanks to you both,


        • #5

          that's fine

          i do know that ps is far superior in channel handling and adjusting than psp. so, if you can do it in channels and that's your interest currently, go for it



          • #6
            Hi Gina,

            Real quick way to do this. Select Red Channel, copy as an Alpha. Then run Polaroid D&S Filter set to remove light dust. Finally copy it, and paste it into your Red channel.

            OK you can work direct on the Red Channel with Polaroid D&S, but I prefer to get it right in the Alpha first.

            Did this on your pic, then a very rough Colour correction with levels. Total time taken about 5 mins (including writing this and posting the image). Obviously there's still work to do, but it gets you in the ballpark pretty fast.
            Attached Files


            • #7
              Gina, FYI, the LAB color space is very different from the others All of the detail is in the L channel. That means you can apply heavy blurring to the color which is all in the A & B channels and you will not impact the detail of the image.
              Regards, Murray


              • #8
                I wanted to see if I could do a quick, acceptable fix. Obviously, it still has some issues but for the 7 minutes it took, it is a vast improvement.

                I too used LAB mode. I used it for the blurring of the color channels and for some sharpening of the luminosity channel. Then I converted it back to RGB and realized that the problem with the red was still a problem. The red channel was duplicated and a quick gaussian blur was applied. The copy was then pasted back into the original red channel. Lastly, curves was applied to the new red channel to fix the color cast.

                Attached Files


                • #9
                  Hi all

                  For those that use Elements I believe you can somewhat follow Murray's procedure. I can separate the Luminance to a layer, which I did. Then using grants tools I copied the green channel to the luminance layer I had produced. Then I blurred the red and blue channels quite a bit. To finish I could reduce the luminance layer opacity somewhat to get the best balance.

                  It worked although not as good as Murray’s but it would save a lot of work in cleanup.

                  Attached Files


                  • #10
                    Thanks for the suggestion. I tried your method and it works fine on the part of the image I saved for the web at only 100k, however, in it's full version (scanned at a res of 600), the d&s filter keeps processing and processing, never to finish (at least so far). I guess I could try at 300dpi, I just have been doing all my work at 600 so far and resizing when done.

                    Thanks for that bit of important info with regards to blurring. I wasn't aware of that!

                    Your version looks great too. This seems to show what I suspected, that quite a bit can be cleaned up in short order before the more detailed work is done.

                    Thanks all!


                    • #11
                      Gina, another way to improve that red channel: copy it and then run Noise/Median on the copy (with a high enough setting to blur out all the scratches/spots etc- say, a value of between 10 and 15). Now go to your channels pallette. Make sure you are on your image layer and not on an adjustment layer and select your original red channel. Then go to Image/apply image and set the "red-copy' as your source. Set the blend mode to darken and leave the rest as it is. Watch those light spots disappear. The beauty about this is that it only affects the light pixels and the dark pixels remain unchanged. You won't notice any significant blurring of the image. Sorry I don't have time to post any pictures but will post later if you need any clarification. Get rid of that yellow spot on her arm by using a Selective Color Adjustment Layer. Choose yellows and then remove as much of the yellow in Yellows as it takes to clear the spot. Fill your mask with black and then paint back with white over the spot on the arm. Another way to do it would be to use your Healing Brush but set it to color. Sample from a good area and brush over.
                      Sincerely Syd


                      • #12
                        You guys are amazing. I'm going to learn so much here.


                        • #13
                          Pepperspray, I'll second that!

                          Thanks so much for another option and clear instructions. I'm going to give it a try this morning!



                          • #14
                            Gina, I had another go at your image. I wanted to see how far I could get without resorting to the clone tool or the healing brush. I wanted to try and clean it up as much as possible by using the filters and adjustment layers thus minimising any clone work. Well, it seems there is no magic bullet but a lot of the damage can be fixed in a few quick steps. Ultimately I had to resort to the Healing Brush to get rid of the worst spots but it was minor work.

                            My first attachment: this is how far I got without using a clone tool.

                            First I opened a curves adjustment layer to correct the color. There are so many ways to correct the color in an image. Here is the one I used here: seeing as the image had a red cast to it, I figured - and I am not sure that I am correct on this point because I have never studied anything on this- that the Green and Blue channels had faded with time. I reasoned the red channel could hardly get brighter as it deteriorated. So I opened my info palette and got hold of my eye dropper and looked for a midtone spot on the red channel in the image (i.e. a value of 128). When I found one I marked it, opened a curves adjustment layer and brought my green and blue channels up to the same value. This got rid of the red cast. I set that layer to 'color' and then did another curves adjustment layer to set the white point. I set the white point at 95 and changed that layer's blend mode to Luminosity.

                            Next to smooth out the colors, I created a new layer, merged visible (ctrl,shift,alt,e) and ran a Dust and Scratches filter (value 6) on it. I set the layers blend mode to color. This evened out the colors nicely and only left a few larger spots but didn't affect the luminosity. You could use Gaussian Blur here but I prefer Median or Dust and Scratches as there is not so much color spread. Nevertheless I still had to mask out the teeth which had become slightly red from color running off the lips.

                            Next came the Luminosity. Opened a new layer, merged visible again and ran a Dust and Scratches but this time with a value of three. This got rid of most of the smaller scratches. Then I set the layer's blend mode to darken. The dark pixels were unaffected and only the previously light pixels were darkened thus minimizing any blurring of the image.

                            On the fourth layer I once again merged visible and did Ro's Quick Degrunge trick on the face, neck and arms. High Pass 9, Gaussian Blur 3 and Layer opacity 25.

                            Finally I did another curves adjustment layer to get rid of the yellow spot on the arm and a high pass layer to sharpen.

                            Although the explanation was long that took all of about 10 minutes.

                            My second attachment: a little bit more work but by no means complete. (Another 10 minutes)

                            Instead of going straight at it with the Healing Brush I once again created a new layer, merged visible and ran the Dust and Scratches filter but this time with a heavier setting until most of the spots and scratches (save the largest ones) disappeared. I black masked this layer, took a soft white brush at 100% opacity and just dabbed on those spots. It is much quicker than the clone tool or the healing brush because it only requires one click. No alt-clicking to first sample and then heal. It is one touch healing. However, if you had CS2 with the new one-touch Healing Brush that would be a different matter. Perhaps I wouldn't use this technique on a face but it works fine for clothing and background.

                            Then and only then did I break out the cloning tools. And there was hardly any work left to do.

                            Finally I adjusted the levels again and did some more sharpening and a color balance layer.

                            And there you have it. Hope this wasn't too long winded and rambling.

                            Sincerely Syd
                            Attached Files


                            • #15
                              Originally posted by Syd
                              And there you have it. Hope this wasn't too long winded and rambling.
                              Absolutely not! Thanks for taking the time to outline your procedure step by step. I'm looking forward to trying this approach, but it'll have to wait I'm afraid due to a holiday cookout! I did try the other approaches in this thread, and actually combined some, but admittedly I still had quite a bit of healing/ cloning to do. It'll be interesting to follow your steps and see how much closer I can get before pulling out those tools. I'll let you know how it goes. Thanks again!



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