4 Replies Latest reply: Apr 2, 2012 12:47 PM by zer0hvk RSS

    Methods for keying footage with a white background

    zer0hvk Community Member

      Hey, guys!

      You've always been helpful, and after trying to find out the answer for myself, I didn't find something particularily useful, so, sorry to bother but I need to ask for your help once again.

      I hope you can help me out.


      So, I have this stock footage of a glass with some cranberry juice, and an ice cube dropping into it:

      http://www.istockphoto.com/stock-video-18264375-ice-into-cranberry-juice-slow-motion.php?s t=fbb23eb

      I've used AE mostly for Motion Graphics, so, keying out footage is something I've almost never had experience with (only with green and blue screen).


      I downloaded the free comp and tried to key it out, but I'm a complete ignorant in this subject. (By the way, I'm not trying to steal it, just testing how to do it, so I can then buy it)


      Any idea / tips on how I might be able to do this?

      I could mask the glass out, but then the ice cube comes in, and the splash, and all this would be kind of a mess.

      I plan on setting it on a white background anyway, thing is, I'm setting a bottle next to it, slightly behind it.

      I tried seting its layer style to Darken or Multiply, but the splashes seem weird when they overlap the bottle.


      Anyway, I'm on CS5, if there's anything else I could clear up to help you help me, I'm more than glad to comply.


      Thanks again! You guys are awesome!

        • 1. Re: Methods for keying footage with a white background
          Dave LaRonde Community Member

          The only thing I can recommend is this: minimize your aggravation.


          Put that bottle in the background on the left side of the screen, where there are no tiny droplets. on a separate layer, roto around the splash that comes out of the glass, and THEN use the blending modes on it.


          This shot won't be any piece of cake.

          • 2. Re: Methods for keying footage with a white background
            Rick Gerard MVP

            The first place to look is the color channels. Look at Blue. It's almost a perfect matte just the way it is. Invert it and a little levels call and you should be good to go.


            Screen Shot 2012-03-23 at 3.34.54 PM.png

            There are a bunch of ways to adjust the blue channel. The easiest is probably with Set Channels and Levels. The simple approach is to use Set Channels to set the alpha to the blue channel then use a levels call to the alpha channel and adjust the black , white and gamma points to make the alphe look the way you want it to look.


            Another way would be to use the levels call first on the blut channel, then apply Set Channels. The quality of the preview is so poor that I don't know which way would work better.


            Screen Shot 2012-03-23 at 4.10.11 PM.png

            • 3. Re: Methods for keying footage with a white background
              Mylenium MVP

              Anything that has lots of white and a distinct foreground color can be unmultiplied based on luminance. Channel Mixer, Shift Channels and a variety of otehr effects are your friend. Combined with adjustments this is pretty straightforward...



              • 4. Re: Methods for keying footage with a white background
                zer0hvk Community Member

                This took me a long time to answer, but thanks a lot, everyone!

                When we bought the footage (1080) things flowed much better, and thanks to your instructions I finally got a hang of KeyLight.

                Thanks a lot for your useful answers, You guys are amazing. I'm learning so much here.