5 Replies Latest reply: Dec 5, 2012 7:05 AM by able123 RSS

    Help with a matte and chroma key

    Soshman Community Member

      blue eye.jpg

      I have a video of this eye ( smaller ) and the iris changes color...and i want to be able to

      have a back ground video where only the eye including the eyelashes  are transparent so i can have another video behind it.

      Problem is that the white of the eyeball and the eyelid is too close and when i try to chroma key out the white between the eylashes and the eyelid

      and the white area below the eyelashes cause the inside area ( eyeball ) to go transparent.


      What i want is the only the eyeball and eyelashes ( eyelashes crisp and distinctive ) so the background video can be seen even between the eylashes

      and the surrounding area.


      What i was thinking and tried was to mask the black part of the eyelashes closest to the white eyeball and then change the white inbetween the eyelashes and surrounding to another color and then chroma key it out. After many filters and masks it became obvious to me that i dont know what i am doing and it seems like it should be a simple process.


      Any help is well appreciated...as usual:-)



        • 1. Re: Help with a matte and chroma key
          Community Member

          I think what you want is not a chroma key thing at all, but rather a " mask " that you can use to make area transparent ( you can make the eye transparent or the area outside of eye ( surrounding the eye ) transparent.

          And it is not simple to do. And it may be very complicated depending on how much your camera and the eye is 'moving' in the video. Each movement requires that the 'mask' changes.


          For me the easiest way to demonstrate this was using photoshop and I only did the mask to make the area around eye transparent. That selection I made to create 'mask' per se was saved as you can see in the channels..and one channel is selected  in sample below to show you the channel ( saved selection ) that I made.


          Each time your camera or eye moves the mask you make from this sort of thing will need to 'move' to accomodate the movement of camera and eye. In a way what you may end up doing is rotoscoping every frame of your video to do what I think you want to do. Or you can use a tracking matte and see how that works out.


          Basically the file I have made in PSD ( with channels you see ) ...would have to be manipulated a bit more to create the 'mask' as a layer you would import to your editor.  For example I could create a new file and drag the channel into that new file and do that as a layer you can then import.


          sample of what I did to illustrate is below. I don't use AE but you might be able to do this in AE. Others can help you with that.


          screenshot eye copy.jpg



          what I used in PSD was the selection tool with different tolerances.. basically you use the selection tool and keep 'adding' to the selection ( shift key ) with different tolerances so you dont end up getting any of the eye selected...and you have to do that in between the eyelashes as needed also...

          • 2. Re: Help with a matte and chroma key
            Soshman Community Member

            Hello Able!


            Wow....thanks for the great response and the work you put into it.


            Actually all that will be moving will be the iris. It will be spinning and changing colors.



            So the sclera ( white part of the eye ) and eyelashes will be static itself but i want to be able to do some Ed Burns

            type panning and zooming


            If i can do what you did in your image above then i will be good to go as the video i have of the iris moving

            and changing color and the white part and eyelashes static should not require the rotoscoping ( not sure i am saying the right thing here )


            Thanks again for your explaination and image!



            • 3. Re: Help with a matte and chroma key
              Community Member

              You're welcome. Was fun to help out and I hope it leads to solution for you. Sounds like you might want to separate the iris from the rest of image too...and also the spectral highlight of ' photo light ' on iris so that it stays in same place as iris spins. If you don't spin it too fast you should maintain the nice radial lines and definition in the iris... so it doesn't blur out too much in the spinning and your export.

              So maybe another 'layer' for the iris and another one for the spectral highlight...Then you can 'position' ( spin- rotate ) the iris and change colors along the way...and the background video plays in transparent area in background...


              My immediate reaction to the spinning iris idea was to use Maya ( then use that exported video in the iris mask ) but since I've never tried anything like that in editor I really have no clue what would look best. And I never made an eyeball in maya either, so I'm at a loss to help further at this point. Good luck !

              • 4. Re: Help with a matte and chroma key
                Soshman Community Member

                Quick Question Able123


                I was working with an editor who uses cs6 and he was showing me how to do all this using the same files and .pproj


                problem was my exports kept showing the mattes and his didnt.


                also had another issue was my mouse is blocked getting from screen 2 to screen 1 unless i find the magic door about halfway down and then it goes over.


                Only thing i did different today was update my nvidia gtx480. They notified me this morning and i updated it and now problems

                could a video card cause this kind of stuff?


                Is there a way to go back to the previous version?


                Thank You!

                • 5. Re: Help with a matte and chroma key
                  Community Member

                  hiya. sorry, i dont use cs6. and i think there's a hardware forum here to help with mouse or video card probs. or maybe someone else here can help you out...

                  good luck !