10 Replies Latest reply: Apr 25, 2012 1:50 PM by jmoore5036 RSS

    Green Screen with Keylight problems

    jmoore5036

      I am trying to remove the green screen background.  I am able to remove it but there looks like wiggling lines around the outside of the person after the green screen is removed.  What causes this and how do I fix it.  I shot the footage on HDV cassette.  Could this be an issue with quality of the footage.  I have tried messing around with the effects and settings in keylight but to no avail.  Any help would be appreciated.

        • 1. Re: Green Screen with Keylight problems
          Dave LaRonde Community Member

          jmoore5036 wrote:

          I shot the footage on HDV cassette.  Could this be an issue with quality of the footage.

           

          It sure could be.  HDV pretty much stinks on ice for keying.  It has lousy color resolution, and it's recorded that way: you can't make it look better.

           

          But proper lighting also makes a HUGE difference in chroma keying success.  Since we don't know if you followed normal good lighting practices, we can't rule that factor out either.

           

          Nor can we rule out that you tried to use Keylight intuitively, which is a big no-no... not to mention counter-productive.

          • 2. Re: Green Screen with Keylight problems
            Mylenium MVP

            +1 to everything Dave said. Keying is an art, not something you do en passant. It requires proper preparation just as it may require additional steps. HDV is certainly not ideal, but not impossible, eitehr. Without some screenshot or something, nobody wil be able to give specific advise, though.

             

            Mylenium

            • 3. Re: Green Screen with Keylight problems
              jmoore5036 Community Member

              Hi guys,

               

              Thanks for the input.  This is more of a hobby thing that I am just learning.  I am quite new to after effects and lighting.  I agree that the quality of the HDV footage is not the best.  It almost seems like shooting video off my iPhone has better quality.  Is there something I can read on proper lighting practice so I can give it another go?  I have been trying different things with Keying and it seems that things are getting better each time.  I just need to make sure that I am not doing this all in vain because the quality of the video is too lousy.  I don't really know what you mean by using Keying intuitively.  Can you please explain more?  I can tell you that the color balance is off but that could be a lighting issue and the resolution of the video doesn't seem to be the best.  I have attached a screen shot for review.  Again I am just getting started at this but have a genuine interest in becoming great at it.  So, please be gentle .  If there is anything else I should take into consideration and should read up on please point me in the right direction.  Thanks again for your help.

               

              Sequence 01.Still001.jpg

              • 4. Re: Green Screen with Keylight problems
                Dave LaRonde Community Member

                Ahhhh, there is a BUNCH of useful information out there!  I googled "lighting for green screen" just to see and came up big time with good stuff.

                 

                There are keylight training resources to be found in AE's Online Help:

                http://help.adobe.com/en_US/aftereffects/cs/using/WS3878526689cb91655866c1103906c6dea-7bfd a.html

                Just look at the second section heading.

                 

                You'll also fine useful stuff on the Creative COW:

                http://library.creativecow.net/search.php?q=keylight+&order=t&view=&cat=14&f%5B%5D=2

                 

                 

                And I have to be frank: from the looks of that window grab, you need help lighting for green screen.  Hot spots on the green screen make life very difficult.  More light needs to fall on the subject than on the background.  The subject needs to be placed away from the background: a good six feet for starters, to reduce a nasty phenomenon called light spill, which is when the color of the background reflects on the subject.

                 

                And don't forget: if you can't get useful lighting instruments, Mr. Sun can be your friend: angle the screen so it's in shadow, add fill light & back light to the subject with reflectors, and you're well on your way to good lighting.

                • 5. Re: Green Screen with Keylight problems
                  Pierre Devereux Community Member

                  Hi,

                   

                  The Creative Cow site that Dave has suggested is really worth the time. the 4-part green screen tutorials are easy to understand, yet highly detailed. It also points you to a very good site that can be used to practice your keying on.

                   

                  You are lucky to be doing this as a hobby! :-)    I have joined a company and the green screen effect is 90% of what we need to do, and I am the After Effects guy - well, i hope to be after a few more months of training, reading and tutorials!

                   

                  enjoy

                   

                  Pierre

                  • 6. Re: Green Screen with Keylight problems
                    jmoore5036 Community Member

                    Ok thanks for all the information.  I have one more question and that would be what kind of camera would be recommended for this type of application and to get the best results without having to sell my house :). 

                     

                    John Moore

                    • 7. Re: Green Screen with Keylight problems
                      Dave LaRonde Community Member

                      Personally, I wouldn't go looking for a new camera quite yet. 

                       

                      You still need to become adept at lighting & shooting for chroma key, which will improve your results significantly.  You still need to understand that pulling a good key is rarely a "one click and I'm done" deal: sometimes it can be a very complex process, with multiple layers, animated masks and rotoscoping. Shooting a subject from head to toe, a subject with wispy hair and see-through objects are particularly aggravating.

                       

                      I'd say you should learn how to pull an acceptable key with what you have first, and save those nickels & dimes.  You might discover you get results that work for you. 

                       

                      If you just can't wait, look at a Panasonic camera that shoots to P2 cards and records in DVPro HD or AVC Intra, not AVCHD.  They're probably the most affordable cameras out there with good color resolution for chroma keying.   Please don't let all the blood drain from your face when you look at the price tag.

                       

                      So what about the price tags on the BEST cameras for shooting chroma keys?  Depending you your needs, they can vary in price from an entry-level Mercedes to a totally tricked-out Corvette.  Lenses, filters, viewfinders, matte boxes, and audio & video recording devices are extra.

                      • 8. Re: Green Screen with Keylight problems
                        Todd_Kopriva Adobe Employee

                        I reiterate Dave's recommendation.

                         

                        Read and view the resources here, especially the ones about shooting and acquiring footage for keying:

                        "keying introduction and resources"

                        • 9. Re: Green Screen with Keylight problems
                          Dave LaRonde Community Member

                          Dave LaRonde wrote:

                          If you just can't wait, look at a Panasonic camera that shoots to P2 cards and records in DVPro HD or AVC Intra, not AVCHD.  They're probably the most affordable cameras out there with good color resolution for chroma keying.   Please don't let all the blood drain from your face when you look at the price tag.

                           

                           

                          Well, THAT'S wrong: I meant to write DVCPro HD, and not DVPro HD. 

                           

                          A search for that fictional DVPro HD would either lead no place, or worse still, someplace bad.

                          • 10. Re: Green Screen with Keylight problems
                            jmoore5036 Community Member

                            Hi Dave,

                             

                            Thanks for all your help and advice.  That goes for everyone who had some direction.  I will definitely start working on my lighting skills and then work my way into better camera equipment in the future.

                             

                            Cheers,

                             

                            John Moore

                            Cosmetic Dental Associates

                            john@33smile.com

                            (210) 696-1220