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							         Steve Cannistra, Light Halo Removal


Light halos around stars can result from internal reflections.
           Steve Cannistra, Light Halo Removal

 Setting up the technique in Photoshop:

1. Use the Elliptical Marquee tool to draw a circle around
   the halo. A feather of 2 pixels for the marquee tool is fine.

2. Select curves (Layer, New Adjustment Layer, Curves).


3. You will now have the curves window open, with a mask
   that selectively permits the star halo region to show through
   (see next slide).
  Steve Cannistra, Light Halo Removal

                               Light halo to be removed




Curves window                                Mask
        Steve Cannistra, Light Halo Removal

Removing the light halo is accomplished by the “inverted S”
technique (patent pending <g>):

1. Bring the midrange of the curves downward.

2. Bring the low end of the curves upward.

3. Bring the high end of the curves downward.

4. Tweak it to look like this (next page):
    Steve Cannistra, Light Halo Removal
The “inverted S”




              Final image with halo removed/attenuated