Blue-screen, green-screen, chroma-key - it's all the same thing. To put simply this is the process of filming a scene, object or person in front of a pure coloured screen (typically either blue or green) so that the colour can be removed later to achieve certain special effects.

The majority of major motion pictures use at least some blue-screen work so chances are you may find a use for it in your own production as well. The most common use for blue-screen is to provide a backdrop for your actors when it may not be feasible (financially or practically) to actually film in the desired location. So if you want your actors to be standing on an active volcano you may choose to find some volcano footage and then film your actors in front of a blue-screen. Using the power of technology you can then remove the blue and replace with the volcano footage. Easy. Well may be not. All this bollocks will be covered in later tutorials but for now we want to just build our blue-screen first...

Materials:
1 x Blue plastic tablecloth roll (100' x 40") from party supply store. (About $13)
9 x 1x3 pine furring strips from home improvement store. (<$10)

Optional for mounting on basement wall:
1 - Can of Liquid-Nails from home improvement store. (About $4)

Tools:
Stapler w/staples (Hardware store style normally used for stapling insulation)
Saw
Level

Step 1: Get a room

Make sure you get a parent or spouse-approved room for the project. The strips used to mount the bluescreen are removable, but the Liquid-Nails will leave a mark on (or strip the surface of) concrete. If you screw them into drywall, the screws will leave holes and the strips are likely to leave a crease. My spouse-approved room was an unused storage room in the basement. (Good for me because it also happens to be the largest room in the house!)

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Step 2: Mount pine strips

The blue plastic is thin enough to see through if it lays against the wall, so you may want to use the strips even if your mounting on plain drywall. For me, I couldn't really mount the plastic against the brick wall, plus the wall would show through. The strips leave a gap between the plastic and the wall, plus they make it easy to mount the plastic by just using staples.

Before mounting the strips to the wall, make sure you measure for fit and cut the strips to size. Also, use a level to mark off a horizontal line for each set of strips. Make sure to leave room for overlap at the center, so if the plastic is 40" wide, space the about strips 36" apart.

Finally, mount the strips along your markings. If you're mounting to drywall, you could use dry wall screws to mount the strips to the wall. Just remember they will leave marks. If the drywall is a solid, light color, you may be able to staple the plastic directly to the wall. The staples will only leave small holes, but there will be lots of them. I was mounting to cinder blocks so I used a can of Liquid-Nails. (It's like caulk, but becomes much harder and stronger. It bond extremely well to brick, concrete and wood.) For best results, I applied the glue to the wall and the wood before mounting. The glue takes 10-30 minutes to set, so you may want to have some extra wood around to lean against the strips to hold them in place while the glue dries.

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Step 3: Add the "bluescreen"

Now we can finally mount the bluescreen itself. Roll out the length of material needed and start stapling! Work across from one side to the other. Use several staples (3-4) per foot to prevent tearing as you pull tension on the material. After going a foot or two on the top end, work the bottom end too. Make sure you pull the material as tight as possible without tearing for each staple to keep the finished screen flat.

NOTE: The strips are mounted horizontally for two reasons. First, this will create a single seam, horizontally, in the finished screen. This is much easier to address in post production than several vertical seams. Second, it's easier to work from side to side along two strips of material, than up-and-down and up-and-down several shorter vertical strips.

I goofed on Step 2, and the strips were too far apart to completely overlap the two pieces.
To fill the gap, I just used some blue, painter's masking tape.
Hopefully, you will learn from my mistake and measure it properly from the start.

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Step 4: Finishing touches

To finish, I added some excess material to the top and bottom as well as to the adjacent wall. (I did cover over the basement door, but the strips are screwed into the door frame rather than glued to the wall.

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THE FINISHED PRODUCT

Get to work Mr. Lucas!

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Best software I've found for keying (DV footage mianly) is the FXHome stuff, www.fxhome.com and try CompositeLab..

Next step up, for DV again, Ultimattes keyers are great, though cost a bit more/do a bit less, but gives nice results (Mainly on hair/semi-transparent stuff)

Things like AE tend to be aimed at film footage, not DV, so give better results if you happen to have stupidly expensive cameras and film lying around, though there are plugins/techiques to get decent results with it..

And as for setting up a green/blue screen, it's not hard at all, just make sure it's fairly smooth, big enough, and half-decently lit (CompositeLab does a good job with crappy backgrounds though, as will Ultimatte if you take a clean-plate image)

Ben - Digg.com