Creative Communities of the World Forums

The peer to peer support community for media production professionals.

Activity Forums Adobe After Effects How do you decide what the alpha layer is when saving in Photoshop?

  • How do you decide what the alpha layer is when saving in Photoshop?

    Posted by Daniel Haskett on May 19, 2005 at 11:14 pm

    Hi there

    I know this is kind of Photoshop related, but its regarding importing into After Effects! Basically I have a black and white image of some poles that I want a bird to fly behind…now what is the best way to do this? Once I manage to render the bird out as an alpha layer I then want to make the poles an alpha matte for the bird so that it is only visible where the bird is not? Would this mean making an INVERTED matte, so that the bird is visible in all white areas around the poles. Oh dear, trying to get my head round alphas, been using the help section and stuff but getting help on here is so much better! 🙂

    Thanks for all your help, actually saving my life,

    cheers

    dan

    John Dickinson replied 21 years ago 2 Members · 6 Replies
  • 6 Replies
  • John Dickinson

    May 19, 2005 at 11:26 pm

    Use the poles as a luma matte. Put the poles layer above the bird layer and from the Trk Matte popup menu for the bird layer click Luma Matte “poles” (or whatever the layer’s name is). Now the bird will move “behind” the poles.

    John Dickinson
    Motionworks
    https://www.motionworks.com.au

  • Daniel Haskett

    May 20, 2005 at 12:03 am

    Hi thanks for your help again but Im having the problem that it does make the bird disappear behind the poles but the poles disappear so it is just the bird there and nothing else!

    cheers

    dan

  • John Dickinson

    May 20, 2005 at 12:07 am

    Does your pole file have an alpha channel?

    John Dickinson
    Motionworks
    https://www.motionworks.com.au

  • Daniel Haskett

    May 20, 2005 at 12:35 am

    Erm…I doubt it, I dont know how to make alpha channels in Photoshop…is it easy?

    cheers

    dan

  • John Dickinson

    May 20, 2005 at 12:38 am

    can you email me the file so I can check it out? john.dickinson@foxtel.com.au

    John Dickinson
    Motionworks
    https://www.motionworks.com.au

  • John Dickinson

    May 20, 2005 at 1:21 am

    Okay here’s what you do:
    Choose Luma matte for the bird layer.
    Create a new solid (LAYER > NEW > SOLID) and give it a color other than black or white.
    Place the solid at the bottom of the layer stack.
    Duplicate the Pier Struts layer and put it at the top of the stack.
    Set the Pier Struts blend mode to multiply.

    You’ll need to crush the blacks on your pier struts layer also because you can still see the bird layer through the poles if you don’t.

    You could also forget the track matte step altogether and just put the pier layer above the bird layer and set it’s blend mode to Multiply. You’ll still need to crush the blacks though.

    John Dickinson
    Motionworks
    https://www.motionworks.com.au

We use anonymous cookies to give you the best experience we can.
Our Privacy policy | GDPR Policy