Behind the Green Screen Part 1

After finishing “First Aid for Zombies” I began to have visions that involved a disembodied head.  And not just one that floated around, but one that talked and said silly things.  Little did I know that it would involve a green screen and a make-shift studio. 

I knew it was possible to do something called chromakey, where you used software to key a specific color out of a scene and then replaced it with something else.  These days movies make extensive use of this technology in order to provide the dazzling special effects their jaded audiences (myself included) demand.  My first guess was that we could do something that involved maybe masking off a dummy head, then figuring out a way to superimpose the “live” head.  I had an idea and was excited!  I told John, my wife and anybody who got within earshot.

Too bad it was a really stupid way to approach the problem.

In fact, upon doing some research on the internet, I found a bunch of tutorials by children showing me just how utterly wrong my initial plan was.  I would need to have some sort of green background and decent lighting.  The green was important because with digital filmmaking, greens are apparently easier for the software to pick out.  The lighting was critical. Background shadows must be minimized, if not nonexistent.  I can then film the subject, whose head I wanted to superimpose, against the green background and then use software to “key” out the green background and replace it with either an image or video I wanted the subject to appear in.

Most cheap film editing packages have this technology built into them.  We used Power Director 9, from Cyberlink. It was the right price and received a PC Magazine Editor’s Choice recommendation and it advertised that it supported chromakey editing.  I spent some time shopping from the comfort of my kitchen, an ice cold beer in one hand, and a trusty mouse in the other.  I managed to piece together a package of three green backdrops of varying sizes, a stand for the backdrops and a set of lights for somewhere around 250 bucks.  Not cheap – but not outrageous either.  I ordered the equipment and then gave myself a goal of trying to superimpose my daughter’s head on one of our cats.

When the equipment arrived, I set it up in my basement.  When I took my daughter down to see it I watched her eyes light up as she said “Daddy it’s like a movie studio!”  That and the smile on her face made the expense totally worth it.

Daddy - it looks like a movie studio!

Here is the result of my first attempt at chromakey.

My next attempt involved fiddling with opacity.

Attack kitty! Attack I tell you!

I was able to key out the images, but was noticing annoying artifacts around the edges of the images and issues with movement.  I either needed to spend lots of time monkeying with lighting or maybe I needed more sophisticated software.

Enter Adobe After Effects.

To be continued…

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One Response to Behind the Green Screen Part 1

  1. Debbie and Kevin says:

    We so enjoyed contributing to the ForZombies even though we were amatures at the acting, but you two zombies were clearly professionals. I am so clad that Alison and Crispin introduced us to you two two, us Brits were so pleased to meet you. Or was that for you to meat us :-) Best wishes from Kevin and Debbie, although I still can think a little, so you didnt eat all of my brain – Ha Hah, perhaps most of it.

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