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Dynamic Range Increase

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  • Dynamic Range Increase

    Hi Richard,
    Would you be interested in developing an action for expanding the dynamic range? The following web site has an interesting procedure for Photoshop:
    and the Fred Miranda site apparently is redoing a similar action for Photoshop.
    This would be real useful where there are bright highlights and deep shadows in a photo.

  • #2
    Technically, the idea that this is extending the dynamic range is somewhat inacurate. The highlight and shadows in the image are still black and white. What you are doing here is just feeding back the highlight exposure into the exposure created for the shadows. It is a fine technique for getting better detail in a high-contrast scene.

    What I am not sure of is if there is really an action that needs to be created. If I were you, I'd try using Blend Mask to blend the highlights back into the highlight of the shadow image. I can't remember where I just worked through that...i think it was right here...but now that I looked, I worked throuhgh the solution alright and never posted it. See the other thread here:

    1. take the two images
    2. copy the highlight exposure over the shadow exposure
    3. align these (if necessary).
    4. Apply a Blend Mask to the highlight layer to mask the shadows -- letting the layer below bleed through.

    As the result will require different blending for each image (optimally) you will be able to do this with Blend Mask, or you may want to apply a luminosity mask (free tools) and adjust that mask with a curve to preview the blending (and allow later changes). In about two weeks I'll be all done with this book and can come back with better detail in the instructions.

    I think an action is the wrong way to go as it is not a set procedure (like creating Channels can be). the only process you can automate is calling the blend mask or luminosity masking procedure, and those tools already exist.

    that make sense?



    • #3
      That makes a lot of sense, Richard. No two images are likely to need the exact same treatment, and the blend mask is flexible enough to handle a lot of them. Thanks for taking a look at it.