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  1. #11
    Staff
    Super Mod
    hark's Avatar

    Re: How to take this shot or make this image?

    Quote Originally Posted by BF Hammer View Post
    I see the star trails in front of the aurora, which is actually just weird to my eye. So he took a long exposure which I presume brought out the ground level exposure and minimized ISO noise. It could be 1 very long exposure or a layer-stack with many exposures. The aurora appear to be more noisy, so a shorter exposure at a higher ISO setting. He then layered them and combined. But again, the trails in front of the aurora look weird to me and I would have either layered different or thrown out the whole project.
    That's a really good observation, BF Hammer.


    › See More: How to take this shot or make this image?
    Cindy - D750, D500, D7200
    Flickr
    and My 2020 Thread

    Where the Spirit does not work with the hand, there is no art
    -- Leonardo da Vinci





  2. #12
    Senior Member
    480sparky's Avatar

    Re: How to take this shot or make this image?

    Quote Originally Posted by BF Hammer View Post
    I see the star trails in front of the aurora, which is actually just weird to my eye. .......
    The aurora aren't clouds, however. Since they're merely a reaction by molecules high in the atmosphere reacting to a magnetic field, they can't occlude any light source behind them.
    Don't mind me... I'm out roaming around somewhere between Zone III and VII.


    Go forth and actuate!


    My Website.

  3. #13
    Senior Member

    Re: How to take this shot or make this image?

    How to take this shot or make this image?
    Thanks all.
    Here is an example I tried in Gimp using "Lighten only" blending mode with two layers. Remark: BF is correct about the flaw of star trails in front due to gimp's (maybe PS too) blending mechanism, but sparky's point (aurora isn't cloud) could also be true. In my example, there are enough objects behind star trails, they should be in front...
    How to take this shot or make this image?-2020-08-08_12-32-12-s.jpg

    How to take this shot or make this image?-starstax_2020-08-09_21-19-28-2020-08-09_21-45-15_gap_filling-comet-s.jpg

    How to take this shot or make this image?-2020-08-08_12-32-12-blending-lightenonly-s.jpg

  4. #14
    Senior Member

    Re: How to take this shot or make this image?

    Gimp does Brighten Only as commutative, i.e., the layer order doesn't matter -- white pixels always come on top! (in my example, I think the small cloud is whiter than star trails and thus leave star trails behind)

  5. #15
    Staff
    Super Mod
    hark's Avatar

    Re: How to take this shot or make this image?

    Quote Originally Posted by blackstar View Post
    Thanks all.
    Here is an example I tried in Gimp using "Lighten only" blending mode with two layers. Remark: BF is correct about the flaw of star trails in front due to gimp's (maybe PS too) blending mechanism, but sparky's point (aurora isn't cloud) could also be true. In my example, there are enough objects behind star trails, they should be in front...
    When blending 2 (or more) images in Photoshop, if there is any problem with stars showing up in front of trees or other closer subjects, you'd have the option to use a layer mask. With that, you'd brush over the stars to hide them making all the stars appear behind the closer objects.

    I never used Gimp to know whether or not that is an option. Glad you were able to give the process a try!
    Cindy - D750, D500, D7200
    Flickr
    and My 2020 Thread

    Where the Spirit does not work with the hand, there is no art
    -- Leonardo da Vinci



  6. #16
    Senior Member

    Re: How to take this shot or make this image?

    Quote Originally Posted by hark View Post
    When blending 2 (or more) images in Photoshop, if there is any problem with stars showing up in front of trees or other closer subjects, you'd have the option to use a layer mask. With that, you'd brush over the stars to hide them making all the stars appear behind the closer objects.

    I never used Gimp to know whether or not that is an option. Glad you were able to give the process a try!
    There are ways to use mask layers in Gimp for various purposes too. Thanks for your tip, Cindy.

  7. #17
    Senior Member
    BF Hammer's Avatar

    Re: How to take this shot or make this image?

    How to take this shot or make this image?
    Quote Originally Posted by hark View Post
    When blending 2 (or more) images in Photoshop, if there is any problem with stars showing up in front of trees or other closer subjects, you'd have the option to use a layer mask. With that, you'd brush over the stars to hide them making all the stars appear behind the closer objects.

    I never used Gimp to know whether or not that is an option. Glad you were able to give the process a try!
    Yes GIMP has layers and layer-masking. I use them often.

    How to take this shot or make this image?-nfl5si9.jpg

  8. #18
    Senior Member

    Re: How to take this shot or make this image?

    Thanks, BF.





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