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Clean selection of hair from this image - how?

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  • Clean selection of hair from this image - how?

    Hi,

    Have been trying the usual channels, calculations (I am a n00b at this though), and refine edge tricks on the attached image to try and get a decent hair selection. I would like to replace the dark-grey background with pure white if possible, although this won't work without a killer selection.

    It was a bit of a noisy image and there is not a lot of contrast between the hair and the background. I have tried to increase this contrast to get a better selection but I am not getting decent results. I keep getting weak selections of the hair and a bunch of pixel noise around it.

    I know I need to be able to clean up the image and increase the contrast or delineate colors but am not having much luck.

    I was hoping that someone here with more skill than me could provide a recipe on how to approach this particular shot, or at least provide a few pointers. I am sure there is something I am missing.

    Thank you for your help,

    John
    Attached Files
    Last edited by John4893; 07-10-2013, 06:57 PM.

  • #2
    Re: Clean selection of hair from this image - how?

    With this problem (which occurs frequently) you just have to accept that there is no automated solution. The edge is too complex to select successfully. The way I would deal with this involves three stages. 1/Create a new background from scratch. 2/ Mask the edge 3/Paint in extra strands of hair.
    To be more precise
    1/ Painting a new background colour, with or without a gradient/vignette is fairly easy. You may want to switch to 16bit temporarily if a subtle gradient is required, to reduce banding. You are going to mask out the hair later, so you can fill the whole frame to start with. It's important to add noise to match the rest of the image. A good way of assessing what type/amount/size of noise you will require, is to use a solar curve.
    2/ Once you've created the new background, reduce the opacity slightly so you can see the underlying image, and paint out the layer mask to reveal the non background elements. You are creating a new hair/background edge now. Choosing the right softness of brush is crucial, but you can go back and forth with the layer mask till you get that right. Also your viewing size is very important. I would recommend having two windows up. One to see what you are doing close in, and the other to see how it works from the intended size.
    3/ Once you've got the edge as you want it, you need to make it look real by painting in hair strands. This is not as difficult as it might sound. You just use a very small hard brush to start with. Sample the hair colour and paint a few strands. Then go Filter>Blur>Blur(or Blur More), followed by Filter>Noise>Add Noise. You may wish to blur again. Try to get realistic looking hair strands. You can also tweak the luminosity and use Hue/Saturation or the Dodge and Burn tools. If you find your painted hair strands look a bit shaky, you may find it helpful to create flowing, gestural marks and then erase back the excess length.
    This may sound complicated, but, IMO, it's actually the only way to go with this type of situation, and if you practice, you will eventually be able to do it almost as fast it has taken me to write this. (Don't worry - I write slowly)
    Last edited by AKMac; 07-11-2013, 01:55 AM.

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    • #3
      Re: Clean selection of hair from this image - how?

      Originally posted by AKMac View Post
      With this problem (which occurs frequently) you just have to accept that there is no automated solution. The edge is too complex to select successfully. The way I would deal with this involves three stages. 1/Create a new background from scratch. 2/ Mask the edge 3/Paint in extra strands of hair.
      To be more precise
      1/ Painting a new background colour, with or without a gradient/vignette is fairly easy. You may want to switch to 16bit temporarily if a subtle gradient is required, to reduce banding. You are going to mask out the hair later, so you can fill the whole frame to start with. It's important to add noise to match the rest of the image. A good way of assessing what type/amount/size of noise you will require, is to use a solar curve.
      2/ Once you've created the new background, reduce the opacity slightly so you can see the underlying image, and paint out the layer mask to reveal the non background elements. You are creating a new hair/background edge now. Choosing the right softness of brush is crucial, but you can go back and forth with the layer mask till you get that right. Also your viewing size is very important. I would recommend having two windows up. One to see what you are doing close in, and the other to see how it works from the intended size.
      3/ Once you've got the edge as you want it, you need to make it look real by painting in hair strands. This is not as difficult as it might sound. You just use a very small hard brush to start with. Sample the hair colour and paint a few strands. Then go Filter>Blur>Blur(or Blur More), followed by Filter>Noise>Add Noise. You may wish to blur again. Try to get realistic looking hair strands. You can also tweak the luminosity and use Hue/Saturation or the Dodge and Burn tools. If you find your painted hair strands look a bit shaky, you may find it helpful to create flowing, gestural marks and then erase back the excess length.
      This may sound complicated, but, IMO, it's actually the only way to go with this type of situation, and if you practice, you will eventually be able to do it almost as fast it has taken me to write this. (Don't worry - I write slowly)


      Nuff said

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