Does anybody know how to make an inexpensive green screen? Because with my budget, I can't afford to buy them from any company. I'll need to know where to buy the materials and make it myself...

Some people think little of me because I don't post movies. Just wait, grasshopper, and I will blow you away...

Hey, Richmond, VA representin.... I was born there, but raised in Florida. Still have family there, though.

As for the green screen...
I might be wrong, and if so, folks, please feel free to tell me. But I think you could burchase, sat a large blue tarp. Build a frame, and stretch it tight around it. Viola, instant blue screen (same diff) Later, in post, simply removes the blue tarp section. The color would be consitent (atleast, more so than if you tried to paint something green, or blue) so it should work. Im sure, if im wrong, people will let you know, but its worth a shot. Good luck.
R. Michael McWhorter
www.tizzyentertainment.8m.com
www.tizzystoryboardartist.8m.com

And you shall know us by the trail of dead.

you need to be careful when constructing your own green screens because of inconsistency color removal because of lighting (which would create a sort of artifacting or blotches of color that aren't screened out.)

bad lighting could also cast a sickly greenish (if you use a green screen) or bluish (if using a blue screen) on the talent.

those can be fixed, but it calls for alot of tweaking with chromo key filters and you may find yourself not completely satisfied with the end result.

you also need to make sure that if you use a blue rather then the much preferred bright lime green, that the talent does not have any blue (sometimes when lit bad and the talent gets a bluish reflection - parts of the blue that is reflected well get eaten away when you screen out that color.)

a possible way to get rid of shadows or reflections of the green screen color is 3point lighting with a large soft fill light facing the talent, and tweak the arrangement of the two side lights until you get a satisfactory smooth and blemish free background.

good luck.

" I won't show you tonight what requires many hours of progressive and
scientific exercises to even begin to make itself visable; besides I
would need space and air, and especially a head of steam -- which I
haven't got."

http://www.lostheadfactory.com

Here's a tutorial on how I built my own bluescreen room for about $30
It's been working great.
Hope this helps.
Have fun.

Actually it's important to be careful with lighting even when using a professional green screen. I once took some shots in a studio with some people against a green screen and we used our own lights and they weren't quite right, so the final product was a little tricky to work with.

Um...don't use a tarp. My friend tried that and it left spots all over the place in the final product. The light just reflects too much.
Go to hardware store and ask them to match paint for you
.
Bright ass blue or green. Green is better though, blue is found in many peoples' eyes and even skin tones while outside.

"I don't have time for film school...I'm too busy making movies" lol

i heard that for a home made green screen it should be a dull type color green. I need some "light" shed on this issue.

Okay, you use blue screens for video (something to do with YUV colour compression) and green screens if you're shooting on film (something to do with the film stock).

Have you tried E-Bay for proper blue/green screen tarps? That's your best option.

Shoot plenty of tests to make sure you get the lighting correct, also so you can practice "keying" it out later.

Richard.

Be careful not to confuse "dull" with "flat".
Sometimes people say "dull" to refer to "not glossy/shiny", which would be correct, but "dull" could also mean "not bright (or saturated)" which is a bad thing for keying.

If you were to use something like a dull, olive green, the background starts to get close to gray, which is next to impossible to key! Argh!

The color itself should be as saturated as possible. "Pure" bright colors tend to work best. At the same time, the screen needs to have a "flat" finish. Not shinny. Most blue tarps are shinny, which is what makes them bad for use as a bluescreen. The specular (shinny) highlights are also brutal to key.

As for which color (blue, green or even red) it should be primarily based on the subject being shot in front of the screen.
Green is theoretically better for miniDV shooting because green is not compressed as much by the format, HOWEVER, it's still not as good as blue if you are shooting some one with whispy blond hair. Green shows through the blond edges much more than blue, complicating the keying process. At the same time, you don't want to use a blue screen if your characters are wearing blue jeans.

Bottom line: You want a uniform well defined color that contrasts as much as possible from the subject being filmed. Achieve that, and you're well on your way.

Hope this helps.
Have fun!

NEVER USE RED! Whatever red colour you choose, it's still too close to flesh colour.

As far as keying colours with MiniDV, it all depends if you're using NTSC or PAL cameras due to the differences in their respective colour sampling.

NTSC uses 4:1:1 colour sampling which is good, especially over multi-generation work.

PAL uses 4:2:0. Don't worry, blue IS sampled it's just co-located with the green in the picture.

Look at http://www.adamwilt.com/ for more info on this.

Richard.

I respectfully disagree. I have to admit that I don't fully understand DV color sampling and how "C-r + C-b = g" when you don't know "C" but you do know "L", but through experience, I would never try to do a miniDV blue chroma key again. If I absolutely had to, I'd do green. Further, while getting a green that is fully saturated (255 green, they call it) is important, making sure the lighting is perfectly consistent is even more important. A common mistake is that people think "even lighting" and point every light they own at the key BG. Don't wash out the key. You're camera wants the BG to be (G-255, R-0, B-0) if you overexpose the BG, it'll add red and blue (to make white). Also, a strong back or top light helps "pull" your subject out of the key (and reduces spill).
good fortune. It's hard to get good results with miniDV.
joren

>> It's hard to get good results with miniDV.

True, but personally, I think a lot of that is because many people focus their efforts on attempts with Color and Chroma keying. The trouble with these is that they are heavily based on how each pixel deviates from a single color sample. The fact that miniDV compresses color increases the challenge.

If you haven't tried using Difference Mattes, you're selling yourself short and ignoring a very effective keying tool. I learned from attempting to key against my very first home-made bluescreen (a painted drop cloth). The bluescreen was a monumental failure, but the Difference Keying technique that I learned from using it has proven to be invaluable.
Here's an example image:


This is an example of everything NOT to do when keying. The screen is textured, has a line through it, shows wrinkle shadows, and on top of all that, I didn't set my camera's white balance properly, making the screen look closer to gray than blue.

As a result, using chroma keying doesn't work. Holes develop in the character's hair, while an edge of blue-gray still remains and that line will just never disappear:


Enter the Difference Matte.
The magic of this technique is grounded in not one, but TWO key improvements over chroma keying.
1 - Instead of a single color sample, difference keying allows for an indiviual color sample FOR EACH AND EVERY PIXEL!
2- Difference Keying looks not just at color, but at Lumanance (sp?) as well. If there is a hint of non-blue around your character due to miniDV compression, you can still get a good key if there is sufficiant Brightness contrast between your subject and background.

In this example, applying Difference Keying instead of chroma actually saved the shot:


I've since replaced the dropcloth with the new, ultra-hi-tech plastic tablecloth in the tutorial above, but I continue to use difference keying instead of chroma to get consistantly better keys with miniDV sources.

Give it a try sometime. You might like it, too.

Have fun!

Precisely, there is always another way to skin a cat (an expression from where I live).

Having unsucesfully tried keying with SVHS and very sucesfully keyed with PAL MiniDV, I can only say ... well it worked for me.

I still say that if you try keying with a red background you're asking for trouble.

Richard.

I had a thought a while ago. What if you locked down the camera for a chromakey set up, had any backround at all(even a living room), and took a picture of just the background. Then have your subject move in with any new props (carefull not to rearange the things in the first shot) and do their thing. If only there was a program that could look at EVERY frame and take out everything that was in the original snapshot frame (without the subject). That would only leave the subject by itself with a blank background. Someone should invent a program like that, BUT GIVE ME FU*#ING CREDIT. My brother told the slogan "Where do you wan't to go today?" as his (screen name?) or something a long time ago (he's a pilot). Later on it was stolen by Microsoft. Anyway, the only problem would be the imense rendering time. What are everyone elses thoughts?

I think you can find software already that'll do something simillar. Obviously you'd have to spend a lot of time setting it all up.

Try http://www.discreet.com/

Richard

What you just described, screenwriter, is fundamentally what Difference Keying is.
There is a bit of a process to get from A-B (A being empty room, B being subject with blank background.), but what you described is essentially what Difference Keying does.
It works best when you have a good background (like a bluescreen or greenscreen) than contrasts with the subject.
Ultimately the process gives you a mask, where pixels that have not changed are black, and pixels that have changed are white or shades of gray.

I know you can do this with Media Studio Pro, Premiere and AE. I'd be really surprised if you couldn't do it with Vegas and Avid too.

Have fun.

Is it posible to do Difference Keying in premiere?
I tried to use chroma, but it results in "flaky" borders around people.

or maybe there is a plug-in I could get?

Premiere DOES do Difference Keying, but it handles things a little differently than Media Studio Pro, so I'm not sure of the exact steps to getting it to work cleanly.
One of the best places to start, though, would be to read this guide to compositing with Premiere:
Transparency & Compositing w/Premiere

Have fun!