12 Replies Latest reply on Mar 23, 2009 12:27 PM by shooternz

    How to cut extra border in a chroma key montage ?

    lanstrad Level 1
      I superimposed a clip over a clip and selected the green color (in Chroma Key - green screen) so I see my people in a desert as needed.

      However, unfortunately there was a border (left, right and floor) that was *not* covered by the green background and I need to make it disappear.

      Btw the people are scaled down to appear far in the background, but the more they approach, the more I get this obvious unwanted framing.

      What's the best approach to make it disappear ? (I tought of adding another color in the chroma key effect, but I may lose some of the people's clothings as well...)

      I am a 2-weeks user of Premiere. Not experienced AE yet and at this point, not too confortable with my few trials with AE... I'd like to be able to do it within Premiere is possible. Unless someone can guide me to a tutorial on the web ? (Not sure what to look for or how it would be called...)

      Thanks,
      Rob
        • 1. Re: How to cut extra border in a chroma key montage ?
          shooternz Level 6
          Apply a Garbage matte to the clip. (FX)

          Hopefully it will work for you. Its a bit busted in CS3

          The floor is going to be an issue for you though.

          http://livedocs.adobe.com/en_US/PremierePro/3.0/help.html?content=WS1c9bc5c2e465a58a91cf0b 1038518aef7-7c57.html
          • 2. Re: How to cut extra border in a chroma key montage ?
            Level 1
            Try applying crop... Not much option to fiddle with but you can do simple crop left/right/top/bottom...
            • 3. Re: How to cut extra border in a chroma key montage ?
              Level 1
              I hope I can explain this correctly for you to understand?

              Open Photoshop and load a frame of the footage into it.

              Create a new layer and using the dropper tool, select a part of the footage that has the colour you want to key out.

              Now fill the new layer with that colour.

              You shouldn't be able to see your original footage now as it's covered by the new layer.

              Select the opacity slider and make it about 50%.

              Now use the selection tool and create a square with a feather radius of about 20 so it blends together with the footage underneath.

              Create a square around your subjects using the selection tool, so that it is within the edges of the border that you want to fill.

              Now cut away the square, which will leave a hole through the centre of the new layer.

              Go back to opacity and make it 100%

              You should now have your original footage, with an area completely filling the border.

              Okay, now save the image as a PSD.

              Open Premiere and load the PSD into your project with the footage you need to key.

              Choose the layer (not merge) that has the Green frame you have just created and put it on the video line above the footage. Expand it out so it covers the length of the footage that needs to be keyed.

              You should now have a green (matching) frame that fills the footage out to the borders.

              Render the sequence out, and then load it back onto the timeline.

              What you'll now have is a piece of footage with a 'complete' green screen that you can now key out.

              I hope that helps and that it's clear enough?

              Cheers, MP.
              • 4. Re: How to cut extra border in a chroma key montage ?
                lanstrad Level 1
                Thanks to both of you. Tried the Garbage Matte and it worked on that job. I think the second option will be very suitable for another one I have to do, and Neil, thanks : you outlined the procedure very clearly - although I'm also green on Photoshop, but it should be ok.

                Many thanks
                Rob
                • 5. Re: How to cut extra border in a chroma key montage ?
                  lanstrad Level 1
                  Neil,

                  I's stucked right from the start... Ok, been able to save a frame from the footage and load it into Photoshop.

                  When I create a new layer, I do not find the "dropper tool" to pick a color in the frame... Help does not provide anything about "dropper tool" although I understand the concept is the same as in Premiere Pro when keying...

                  Thanks for helping again,

                  Rob
                  • 6. Re: How to cut extra border in a chroma key montage ?
                    shooternz Level 6
                    This type of work is best achieved in After Effects where matte work is very comprehensive. eg inverted and softened edges as well as keyframe tracking. Keying is superior in AEFX as well. (Additional settings and control.). That notwithstanding...Premiere can do a reasonable job if the key scene is shot very well.

                    The Garbage matte technique totally eliminates the un necessary "photoshop" workflow outlined above. Its is so simple and what it is designed for.( Why paint in an area that you are going to remove with a Key filter?.)
                    • 7. Re: How to cut extra border in a chroma key montage ?
                      Level 1
                      Okay, the garbage matte is the best way, but if you'd still like to try the Photoshop route, the Eyedropper Tool is what you're looking for.

                      Sorry, I'm so use to calling the Dropper tool!!!

                      In Photoshop CS3 it's the 3rd tool from the bottom of the tools menu you see on the left of the screen (in default view).

                      Hope that helps, Cheers, Neil.
                      • 8. Re: How to cut extra border in a chroma key montage ?
                        the_wine_snob Level 9
                        Neil,

                        I read "Eyedropper," in your post. Guess that I just knew what you were referring to and automatically made the correction.

                        Lanstrad2008,

                        The Eyedropper is part of a 3-Tool group: Eyedropper, Meausring Tool and Color Sampler (in PS CS2 and for most previous versions back to about 4). By default, it comes up selected and on top of the other two. Note: when you use it, look at the Options bar, just below the Toolbar at the top of the interface. There, you can set the Sampling from Point to 5x5 pxl Sample. Depending on your source material, Point, or 3x3 should work best. BTW Neil's method is a lot simpler to do, than to read. Much in Photoshop is that way. It takes about four clicks to make something work, but 2 pages to tell you how to do it! That's the nature of the beast.

                        While AfterEffects has some great Keying features, for what you want to do, Neil's PS method is very good. However, if the Garbage Matte works, that is probably the most simple of all, though as Craig points out, some aspects of it did get broken.

                        Hunt
                        • 9. Re: How to cut extra border in a chroma key montage ?
                          lanstrad Level 1
                          Neil,

                          Once again many thanks for this. Hopefully you'll get this new reply/question:

                          When you mention : "Now use the selection tool and create a square with a feather radius of about 20 so it blends together with the footage underneath. Create a square around your subjects using the selection tool, so that it is within the edges of the border that you want to fill. "

                          I've tried to figure out both in Photoshop CS3 and CS4 how (where) to do this... Other steps seem ok, but I can't figure out exactely how to do this... I imagine this is something simple - probably my "green" status again...

                          Not sure also about the square : do I have to create one square only or two ? (you mention to create suare in two distinct phrases.)

                          I have tried to find a visual procedure for this but can't find it - most likely because I don't have a "name" for it...

                          Many thanks again,
                          Rob
                          • 10. Re: How to cut extra border in a chroma key montage ?
                            shooternz Level 6
                            How did you get on when you tried the simple "Garbage Matte" procedure?
                            • 11. Re: How to cut extra border in a chroma key montage ?
                              lanstrad Level 1
                              With the garbage Matte, I was able to hide things and bet the background footage until I got too close to the subject. Then, I get hands (of the subject) moving and disappearing as soon as they enter the matte :-)... A "better" but not yet "perfect" result.

                              I also noticed that playing with both parameters (longitudinal and vertical) allow to get closer, thinner - I might get through when I take time to play longer with both. I used the 4-points g.m. - Never tried the 8 point : would I get more control ?

                              Thanks,
                              Rob
                              • 12. Re: How to cut extra border in a chroma key montage ?
                                shooternz Level 6
                                You can keyframe animate a garbage matte.
                                ie move the matte over time.

                                Yes , an eight point gb is more versatile.