5 Replies Latest reply on Jul 29, 2009 12:59 PM by fadoogen

    dealing with reference points on green screen?

    fadoogen

      I'm putting together a little green screen shoot involving a pan across a table top with glasses sitting on the table.

      I was gonna mark the green screen to track the background, so i can lay in a layer of a bar scene in post.

       

      my amateur question is how do you deal with keying out the tracking points on the green screen in post?

      should i make sure the marks on the green screen are a certain color?

      just wondering how it works when i pan across the glasses and see the markers in the background thru the glass?

       

      thanks!

       

      dean

        • 1. Re: dealing with reference points on green screen?
          Adolfo Rozenfeld Adobe Employee
          just wondering how it works when i pan across the glasses and see the markers in the background thru the glass?

          Not easy. Isn't it possible to place the tracking features somewhere else, that wouldn't show thorugh the glass?

          The thing with glass is refraction, not easy to clean-up.

          1 person found this helpful
          • 2. Re: dealing with reference points on green screen?
            Mylenium Most Valuable Participant

            fadoogen wrote:

             

            just wondering how it works when i pan across the glasses and see the markers in the background thru the glass

             

            Avoid it at all cost. Painting it out will never look real, no amtetr how much you try. More to the point: If you cannot avoid it, create them (along with the table) in 3D instead of shooting them on the set. The rest depends on what tracker you use. If it's one of the smarter tools like mocha or one of those 3D matchmoving tools, you only need some form of pattern with a minimum of contrast, which could be light green tape on the darker green cloth. If you use AE's tracker, more contrast is advisable, so use dark red or black markers in positions that can easily be painted/ masked out after the track.

             

            Mylenium

            1 person found this helpful
            • 3. Re: dealing with reference points on green screen?
              Rick Gerard Adobe Community Professional & MVP

              The best option for tracking markers is to make them the same color as your background but about 1 stop lighter or darker in color. Most tracking software will handle this difference just fine. The second thing you should do is to make the markers big enough so that they are at least 15 to 30 pixels wide in the shot. They have got to be big enough to track. The third hint is to use as much depth of field as you can so the edges of the markers are sharp. Avoid motion blur and out of focus markers.

               

              Make sure that your markers will show the perspective. Don't just put them on the back wall. You need at least 4 on the table top and about twice that many on the back wall. Markers that have different geometric shapes are also easier to track than circles. Triangles, crosses, squares...

               

              Try and plan your shot so that you don't have markers passing through the glass...

               

              Last hint.. This is a big one. If you want to key glass remember that glass is highly reflective. Put as much white behind the camera and on the sides as you can so that the glassware looks good and has interesting reflections. If you have a sample of the bar texture or the background see if you can place that strategically so that the reflections show up in the glass.

               

              Now that I'm done with the hints, here's a requirement. Don't shoot DV or HDV or any other color space compressed original footage. You need all the color information you can get to pull a convincing key with glassware as your main subject.

              • 4. Re: dealing with reference points on green screen?
                fadoogen Level 1

                wow,

                thank you so much for your advice, Rick.

                 

                -dean

                • 5. Re: dealing with reference points on green screen?
                  fadoogen Level 1

                  thanks man!

                   

                  -dean