Green Screen

More than a few folks seemed interested in the green screen our group used in our video on Sat. It's super easy todo and a perfect diy project that cost me less than fifteen bucks, but I had the lights and stands already so it might cost you a bit more. I used fabric cuz it's less expensive and more durable than using poster board and I can transport it anywhere. Another common diy green screen is just painting a wall, but try and move that to a location.

 

Making the screen

If you have a way to hang your screen and light it, it will cost ya about $12. If you are starting from scratch this will cost ya up to $60 depending on what you have at your disposal.

The stuff for this diy is from Joann Fabrics and Home Depot:
green or blue fabric
    two 10' x 4' pieces of fleece, $5 ea. on sale
    hem tape, $3.99
a way to hang it 
    one 1/2" x 10' piece of metal conduit, $1.79 
    three connectors, $4.25 ea.
2 lights
    two shop lights, $9.00 ea.
    two 150 watt daylight balances bulbs, $7.00 ea.
2 light stands
    two boards 1"x 2"x 8', $0.75 ea.
    two coffee cans, free
    quikcret, $2

I purchased two 10' x 4' pieces of fleece fabric on sale from Joanne Fabrics for just under $10. I used fleece cuz it doesn't wrinkle as much as cotton or the like. Wrinkles equals shadows that will cause you no end of trouble in post production. Believe me when I say you'll be happy not to have to iron your screen.

Green and blue are used in the movie industry cuz it's not a primary color our skin tone, making it really easy to pull out of a video clip. Yellows and reds will cause problems when you remove it from the clip.  In theory you can use any color, but in practice it is another story entirely. So stick to green or blue.

I didn't take an pics of my build process, but these guys did in case you need the visuals.

Green Fleece, PVC stand

Use the hem tape to attach the two pieces of fleece together. It's a hot glue, just place the tape between two pieces of fabric, run a hot iron over it and they are joined. Ta-Da! I put fleece together lengthwise to make a 10' long by 8' high green screen. I also used the tape to form a 3" loop along the 10' length to run my hanger through.

On to the hanger, I used a 1/2" x 10' piece of metal conduit as a hanger, $1.50 from Home Depot. PVC or even a wooden dowel will bend for this big of a screen, if yours is small they are very useable as hanger material. I cut the conduit into four sections (Home Depot will cut it you) and I used 3 connectors, at $4.25ea., to be able to put 'em back together. Cutting up the conduit makes it way easier to transport and gives some versatility in set up as well.

Coffee can light stands

I have a nice photography rig and I used a few light stands to hold up the screen durning filming. If you don't have that and staying with the diy theme, you can two use a 1"x 2"x 8' board, $0.75ea, stuck in a coffee can with some quikcret, $2. Two bucks of quikcret will buy you more than you need. Dump the Quikcret in the coffee can and add water and wait a few minutes and put the board in the center. Now you have screen stands.

If you want to  see the stands in action you can watch this vid.


Now that you have the screen and it's hung, you gotta light it separate from the subject (person). Home depot to the rescue again, I use two shop lights, $9 and 150 watt daylight bulb in ea. In our filming I clipped them to chairs. When you film, make sure that these lights hit the screen evenly with no hot spots.

Ideally the person will be lit separately, stoplights can be used for this also. But this really isn't the place for a diy in my opinion. You can use shop lights, but I would purchase diffuser paper to soften the lights. Soft light is generally more flattering.

I used my fancy lights, (read:expensive). Checkout the diagram to see a simple setup. The person is lit separate so that the green can be pulled out easier. If you have the space, you can use ambient light and not light the person separate, but be prepared for a lot of fiddling in post production to fix color.

The screen is hung, the person is lit. Shoot to your hearts content. Now on to the post production.

Remove the green in post production

This is the easiest part, it is three clicks and moving two sliders. I use Adobe After Effects, if you don't have it you can get a free 30 day trail.
In After Effects go to Effect, then keying and then click Keylight(1.2). That's one click.

Then in the effects panel click the eyedropper next to Screen Colour, two clicks.

Your cursor is now the eye dropper icon, click the green in the video. Poof!

Green is gone in three clicks. Easy peasy.

If there is still green in your background, there are two sliders to adjust in the effect panel to clean it up. Check out this tutorial to see it in action.

Three clicks and blamo green is gone

Most other editing software makes it as easy as this, just google how to green screen in the software of choice.

After you remove the green screen from your video, you can place your subject in front of anything you can imagine. Google "free stock images" for a nice background or make/use your own. I also used free stock music btw.

Light is the key for any special effect to be believable. So if your main light on the subject is coming from the left, then make the background light come from the left. Lighting is something we all know intuitively and we all know when it is wrong.

Fake brick wall, yup fake

I created my background with this in mind, see the bright "light" in the upper left corner? It actually flickers in the final video. And there is a dark area in the lower right.

Look up at a wall right now, really, there are bright areas and dark areas. Your new background should too. People make entire carers from lighting stuff, so keep in mind this is a way simplified intro to light.

The blue lines are guides in AF

This is the democratization of media at it's finest. For little money you can implement some really amazing effects.

You don't have to limit this to a giant screen either, think of what you could do by holding a green piece of poster board, or wearing a green shirt?

To do any of this a few years ago, you'd of needed access to a very spendy studio, an even spendier professional and spendier still software. If you have any questions, I'm happy to share what has been shared with me.