thanks,
I will do some tests to see how it comes out. Are classes are on 3 days and the greenscreen doesn't move so I guess i'll paint it there before the event :)

Not that this option would be considered that portable - but what we did once was to go out and buy a roll of the cheapest white vinyl flooring we could find - got about 10 feet maybe. We painted the backside of it and hung it from C-Stands. The expensive part was the paint which runs between $15 - $75 a gallon depending on the brand.

Nothing portable, short of a Flex Drop from Photoflex (about 250.00) really works well. Foam core works, but if it has creases where it joins, it's a real problem unless you want to do a lot of software masking. Mike Gunter did an awesome article on this, found on the DMN, where he used a specific cloth that he found at Walmart, and used it with stretch pins. It actually works quite well. But it has to be that shade for the lighting to work well, he has the Walmart fabric # and everything. He built a 30' screen for under 25.00

I use masonite - it's strong, smooth, won't buckle and holds the paint well.

Don't bother spending $75 a gallon - just pick a bright - heavily saturated paint.
Green is genrally a better bet, but blue is fine, as well.
Vegas will grab any brightly lit, well chroma-ed color and use it for a key.
It doesn't have to be any particualr color. Just make sure that the talent isn't wearing that color for wardrobe.

My first idea was to use 2 or 3 4x8 foamcore boards and use green ducktape to hide the joints. I can make my local homedepot scan the ducktape and make a color mix very close to it.
The cloth works well but have some limitations, mainly depending on the sort of fabric it will easily fold (ours folded a lot) which makes thinhs harder.
I will also check masonite, might be a durable solution, does it require some white paint on it before ? Flexdrop are very nice, we don't have the budget for it right now :(
Thanks for the advices :)

Instead of trying to match the tape to the paint, why not tape the pieces first then paint over both?

This seems very logical :) Thanks for the tip

In my day of doing a lot of bluescreen work we used painted foamcore quite a bit. Be advised it is fragile and much of it will be trashed at the end of the shoot. But we always kept it around to cut up and use for masking on subsequent shoots. I suggest regular masking (not duct or gaffers) tape to cover seams - lighter weight, cheaper, takes paint easier. We kept lengths of painted tape handy (usually stretched along a small step ladder) to tear off for quick patches or background touch-ups.

Actually, it does matter what the color is, even with Vegas.
With DV, you are already throwing away half the color, half the light. Green contains a subtiantially greater luma (correct greens) than does blue. Or most other colors that are not part of the common spectrum.
Sure, you CAN pull other colors, use masks, use garbage mattes, etc, but all this is hard, and extra work. Truth be known, analog is *generally* better for chromakey work anyway, due to the lack of pixels in the recording stage. 4:2:2 is certainly better than DV, but all of this is moot in this thread. 4:1:1, even with Vegas' very nice sampling and upsampling in the DV process, is still a hard pull for great key work. Use green, you'll be MUCH happier that you did. Use the correct green and light well, which is the other half of the equation, and you'll be very happy. Screw with either of them, you are asking for troubles.
There are 2 tutorials and one article on this subject on the Sundance site, and this is something we teach regularly in our PPT class.

Hey Spot,
you mentioned an excellent article mike gunter did about how to put together a green screen , and said it was on DMN, do you have a link to it , I have searched and i can't seem to find it.

thanks

They make DV screens now - colors that are specific to how DV looks at the color.

There may be others but I know of 'Digital Key Green', 'Digital Key Blue' and 'Digital Key Red'

Thanks for input on color selection, Spot.
I admit that the majority of my chroma work (extensive) was done first with high end Ultimatte hardware, and then later with BetaSP and AVID MC.

On the other hand, I have had very good success with "approximate" bright green, bought at Home Depot and Vegas. On the third hand, these chromakeys were distributed as QuickTime on CD ROM, and the lowered resolution makes up for a lot of problems.

v.

All this talk about chromakey paint and colors reminds me of the best chromakeying solution I ever found. Play Incorporated, makers of the Trinity system and the Snappy frame grabber, came out with a system called the "Holoset." Basically, it was a ring of bright blue or green LED's that attached around the camera lens and a special reflective fabric that hangs behind the subject. You light your subject as normal, but when you turn on the LED emitter, the fabric magically reflects the most intense, evenly lit and monochromatic chromakey surface you have ever seen. Well, only the camera sees it, to the naked eye, it still looks like a piece of gray fabric. Since there isn't actually a green or blue surface behind the subject, there is no color spill reflecting off of the edges of the subject. The result on camera was simply amazing and, since the color is so even and a single narrow green or blue color, it is VERY easy to set the key in any NLE.

The downside is that it is cost prohibitive to do a large set because the fabric is so expensive, but it is great for talking head stuff. Unfortunately, Play is no longer in business, but BH Photo still sells the fabric. A 3.2 x 4.6 foot piece is around $280. A 16.4 X 4.6 foot piece is about $1,600. I own a Holoset, but I'll bet that someone could make their own LED emitter array and just buy the fabric from BH Photo, or maybe you could rent one from a local production rental joint. Just thought I'd mention it.

James