Re: [APML] Red / H-alpha work with film

[Roland Roberts <roland@astrofoto.org>]

>>>>> "Jeff" == Jeff Ball <jeffball@zoominternet.net> writes:

    Jeff> That is one question I have, how to do a color gradient
    Jeff> correction in an area without altering the star color
    Jeff> balance?  Any help would be greatly appreciated.
 
With Picture Works Pro (PWP, I've done an overall color correction the
will take your nice white (burned-out) star images and give them a
color.  To avoid this, I create a mask, selecting by value so as to
get all the star cores.  I then apply the color correction using the
mask to keep the stars white.

You should be able to do something like this in PWP, adjust for
whatever you are using:

    1. Create a mask using the select by value.
    2. Create you color gradient correction.
    3. Composite the color gradient with the mask, setting the mask to
       zero out the correction in the area of the stars.
    4. Composite the color gradient from step 3 with the original image.

roland
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Roland B. Roberts, PhD                             RL Enterprises
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