9 Replies Latest reply on Jul 6, 2015 6:35 AM by Mathias Moehl

    Keylight issue


      I have footage that I'm attempting to key out a color, the only problem is that there is a shadow on the actor's face. If I take the key up too much, then his body begins to ghost out, because the person who shot it decided to use the same color gel as the background.


      On the Screen Matte, if I bring the Clip White slider down past 75, the halo gets TERRIBLE. He moves too much for me to go in every frame and take it out individually without this being torture.


      Would the Color Difference Key help at all?

        • 1. Re: Keylight issue
          Mylenium Most Valuable Participant

          Without seeing it nobody can really tell you much. You might get around this issue by using some pre-processing channel trickery like extracting a matte based on Hue and feeding it into Keylight as a holdout matte. otherwise you may need to come to grips with the fact that you have a tedious roto/ mmasking job ahead of you.



          • 2. Re: Keylight issue
            msigurdhall Level 1

            Here's an example of what I'm working with, though I converted it to a JPEG so it would show up on here. The original files are DNG


            Agent Burke - Cal at window FX MC 05.jpg

            • 3. Re: Keylight issue
              Rick Gerard Adobe Community Professional & MVP

              The first thing I would do is some color correction to bring up the blue. The shadow on the left side of the image has driven the blue to nearly black. Aim for something like this:

              Screen Shot 2015-07-04 at 10.54.33 AM.png

              If you are ever around when the original footage is shot put some light on the blue screen. It should be at somewhere close to the 50% if you have a scope and move the talent away from the background. (Flesh tones somewhere around 70%, screen 50%)


              I'd apply color correction, then add do your keying, then, if you want this under exposed look, you can use the keyed footage as a track matte for the original. You'll need to do some manual spill suppression if you go with the track matte method or you can add color correction after the key. It would look something like this: (it helps if you work in 32 bit)

              Screen Shot 2015-07-04 at 10.52.22 AM.png

              • 4. Re: Keylight issue
                msigurdhall Level 1

                Hi Rick,


                That sounds like a great idea. The problem is that she nixed the idea of me being there when it was shot. That was my first instinct (as I have worked on many sets). The director wanted a glass effect done with the actor looking at a skyline, and I told her I had a similar enough camera that I could shoot a reverse shot to get the reflection I could put in the "glass" that I'd create. She didn't like that idea.


                I'm getting cut off by her left and right. What she's telling me is that the actor needs to stay EXACTLY AS SHOT. I've been on Lynda.com to try to figure out all the challenges her footage has been giving me (probably have watched 20 hrs of video at this point) to try to figure out the intricacies of what she's wanting).


                Without having to rotoscope/matte out the actor in EVERY frame, is there any way that I can brighten only the bluescreen with a color correction effect so that I can key it out much easier? This could REALLY save me, if  you know this trick, as she's dead set on using this gel and a blue background instead of green or white.



                • 5. Re: Keylight issue
                  Rick Gerard Adobe Community Professional & MVP

                  I made that shot work with a simple inner matte and exposure control. You should be able to pull a good key, use that as an alpha track matte, then color correct and do your compositing. The track matte will give you exactly as shot with all the blue spill on the edge of the actor and especially on the back of his head which was the reason for the hold out matte. If there is more shooting to do plead for a better exposure. The hardest part of this project for me would be to deal with footage that is way under exposed.


                  Your director needs to understand the limitations she is imposing by under exposing the footage. You can set your exposure in post with a lot more control than you can fix under or over exposure in the camera. That actor, a couple of feet further from the blue screen and with some light on the blue screen would have been a very simple key. The way she shot insisted on shooting the shot caused problems in post that can only be solved by throwing more money at it.


                  If I am not invited to the set I insist on seeing sample footage before bidding on any job. I'd add 40% or 50% to this job because the footage is out of spec for post production and requires lengthy and expensive corrections before it can be used.

                  • 6. Re: Keylight issue
                    msigurdhall Level 1

                    Thanks, Rick!


                    I pretty much told her EXACTLY what you said when I first saw the footage. I'm much more of an editor who has a lot of experience with Photoshop, so I was thrown into this role (due to budgetary reasons). I had a feeling that AE could do this, but I couldn't quite figure out how. I'll get back to you after I play a little more, now that I know what I need to do.


                    I really appreciate your help. You may have just saved me several more profanity-ridden hours of attempting to fix this footage!

                    • 7. Re: Keylight issue
                      msigurdhall Level 1

                      So, because I'm still trying to figure this out... to create an inner matte, would I have to rotobrush each frame and then inverse the selection so that it would select everything outside of the selector? Or is there a simpler way of doing it?

                      • 8. Re: Keylight issue
                        Rick Gerard Adobe Community Professional & MVP

                        No, just a rough animated matte around the actors head. You can look at the Combined Matte (see screenshot) instead of Final Result to see where you need the inner matte. If the actor doesn't move much in the frame just a few keyframes should probably do it. To get to the point where I needed to draw a matte I just worked a bit with the screen gain and balance then clipped the white until I got a clean matte for most of the image. You just have to hold out the area that doesn't key very well. Here's what my matte for this frame would look like before assigning it to the inside mask.

                        Screen Shot 2015-07-04 at 10.44.24 PM.png

                        • 9. Re: Keylight issue
                          Mathias Moehl Adobe Community Professional

                          As an additional tip: I would touch the clip black and clip white parameters as little as possible.

                          In this tutorial, I give an overview of which parameters you use best to tweak the result:


                          Guru Lesson 5 - Bluescreen Keying and nested Compositions | mamoworld