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Old September 11th, 2003, 08:17 PM   #31
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Poor mans bluescreen?

I was just thinking about using one of them big blue tarps that you see all over the place as a bluescreen, would this work at all?

The only problem I see is that they have a texture to them, and that might affect the chroma key....

Other then that, a 20x16FT one at the home depot is only $18.

http://www.homedepot.com/prel80/HDUS...SearchStr=tarp
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Old September 11th, 2003, 08:24 PM   #32
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They are also fairly reflective compared to say plywood and paint, but if you light it really flat you might be able to get away with it.
Let us know how it works ;)
Don

BTW, is the reason for fewer posts lately that you've gone back to school or???
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Old September 11th, 2003, 08:28 PM   #33
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Yeah, mostly school, and I haven't been shooting much video lately. =/

I'm going to buy the 9x12FT one for $8 (which is still a decent size, even though 16x20 is huge) and see how it works...

My neighbor has one in her yard, and thats where i got the idea from, and it didn't look too shiny/reflective to me....
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Old September 11th, 2003, 09:49 PM   #34
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As I said it's shinier than plywood and flat paint but it might just work. You might also try "dulling spray" that you can buy at most hobby stores and it does just what it's called. It dulls the surface reflection. I use to use it many many years ago when I would shoot glass or metal for catalog stuff along with the right lighting of course.
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Old September 11th, 2003, 11:10 PM   #35
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Nah Alex... don't do it. It WILL be too shiny... absolutely. The BEST possible option is to paint a smooth wall with chroma green or blue. (DV likes green best by the way.)

If that isn't possible you are left with two pretty good options.

1) Get a roll of seamless paper in chroma green. If you live close to any major city then check with photographic or cinema supply. You can get a roll of seamless background paper in "stinger" which is chroma green and it costs less then $40 for a roll which is 9' wide by THIRTYSIX feet long! Meaning it's practically DISPOSABLE for each shot!

To get a uniform background put two loops of rope around your trusses in the garage (or bicycle hooks)... then run a metal pipe through that so it hangs near the ceiling. You are going to run that through the cardboard tube that your paper is on. Be sure to clamp the paper with the appropriate amount coming down or else the weight of the paper will unroll the entire roll right before your eyes! It's best to have somebody help you set this up the first time and every time.

Option 2) is chroma fabric at $17 per yard. You'll need AT LEAST two yards and preferrably 3 so you can hang it up on a wall and have enough to curve down, out, and over whatever your talent is standing on.

Finally the most crucial part of all this is even lighting. You can get that with fluorescents. I'd recommend you get some Kino tubes for $20 or so each and put 'em in normal household fluorescent fixtures. You can use these for other purposes as well... such as softboxes.

That about sums up all my advice... everything else gets pricey.
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Old September 12th, 2003, 12:46 AM   #36
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Alex, in case Don and Matt haven't turned you off it enough, those blue tarps are shiny like glass. Don't even waste your time on it.
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Old September 12th, 2003, 06:05 AM   #37
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Aye aye. I'll check out some of them options, Matt, thanks.

A friend of mine pulled off a nice bluescreen with blue sheets of posterboard, so I thought if he could do it with that, then I could do it with this, heh.
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Old September 12th, 2003, 06:34 AM   #38
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Matt,

Know where the chroma fabric you mentioned at $17 a yard can be purchased from online?
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Old September 12th, 2003, 08:36 AM   #39
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Filmtools.com has chroma fabric listed at $17.90 per yard and it's 60" wide.

Studiodepot.com has Rosco chroma listed at $95 for a piece 48" wide by 10 YARDS long.

I got my price from Cine Services here in St. Louis. They have an EXTREMELY limited stock onhand, but they did have chroma green and blue... as well as the seamless paper. At their store the chroma fabric is 84" wide (6') and that's nice... plus it's just $17 per yard.

They do have a website at Cineservices.com and they'd probably be tickled to get called in orders from other cities... so if you do call them be sure to tell 'em matt gettemeier sent you!

Seamless paper really is CHEAP. The thing about it is that you need to have a friend help you so you don't CREASE it... if you wrinkle it up then FORGET your chroma key. You MUST have your metal pipe hanger ready to go before you start.... also be sure to get those pony clamps (or similar) to hold the paper from completely unrolling!

If you guys want to take this chroma keying to the next level then get yourself some colored fluorescents... green or blue tubes... and pop 'em in ordinary hardware store fixtures. Then flag 'em so they get ONLY the background and keep your subject independently lit in the foreground... even before you dump that video into your computer you'll be getting giddy at how well it will work. When you look through the eyepiece or LCD you'll see that the green areas don't even look real... it looks like a flat digital background from the start. Hence it makes chroma keying work perfectly.

That's how all the pro's do it in Hollywood... and those tubes are less then $25 a pop! If you're over 25 then I don't have to tell you how cheap fluorescent shop lights are... just be sure they have the high-frequency electronic ballasts and they'll work fine... even if they don't look like Kinos.
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Old September 12th, 2003, 08:51 AM   #40
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If you have at least $100 do a search on ebay. I purchased a cloth 12'x12' greenscreen online (with gromets for hanging, etc), for less than that. Might be worth your time.
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Old September 23rd, 2003, 03:35 PM   #41
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I'm struggling a bit with chroma-key. Can you help?

Hey gang. I've been trying to get my chroma-keys perfect and it's wearing me down. I can get a good seperation with either blue OR green screen. I can even get a sharp, detailed edge between my subjects and the key.

The problem is that it seems like I have a choice of having a bit of transparency to my subject. (Too much to be acceptable) or else rediculous jaggies surrounding them if they aren't transparent at all.

The transparency allows too much of the overlay detail to come through their body. It's crap.

I've set up a chroma wall with seamless paper and it's evenly lit with Kino tubes in homemade fixtures... I've also played with the light levels on the subject and it's definitely been a bee-otch since I haven't figured it out yet.

My system is a Canopus RT system that's supposed to be particularly good at this... so I'm just wondering how I get my subject CRISP with ZERO transparency and a clean edge of seperation between him/her and the key?

I even tried the magenta gel and backlight... what do you think I'm doing wrong?
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Old September 23rd, 2003, 03:56 PM   #42
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This procedure will work with any video editing app that has layers (I use Adobe Premiere 6.5, but I don't see why this technique wouldn't work with any editing app). This info applies specifically for Adobe Premiere 6.5, however.

Lets face it: Premiere's chroma-keying sucks, but I've found a way to get very professional looking composits using only Premiere with no additional plugins or other software:

1. Shoot your green-screen footage. It's good to have a well lit green-screen, but even lighting is more important then brightness (You'll see why in a minute).

2. Capture your footage. Once you bring it into your editing app, load your footage on the first overlay track (layer 2 for Premiere)

3. Apply the filters to adjust the saturation levels of this video clip to 200% or better, especially for the green. This will really bring out the green background. Sorry, can't remeber the exact name of the filter, I'm not in front of Premiere right now, I'm doing this from memory...

4. In the transparency settings, choose Chroma-Key from the drop down and use the eye-dropper to sample the green background, then choose "Mask Only" on the right side of the dialog. Close the Transparency window.

5. Sometimes, you will have to clean up parts of this mask, so if you need to do this, simply create a title and apply white or black shapes to the imperfections to get rid of any trouble spots. You may have to keyframe some of these things so you might have to create multiple titles, it just depends on how "clean" your green screen footage is.

5a. At this point, you can either create a virtual clip or render out this video into another clip. I usually just render this out because my wife says I can't feed both my video jones AND my computer jones (I have a slow PC). We'll be using this clip to create a "cookie-cutter" for our composited final video

6. Make a new project, load your clips, including the mask you just created, and put your plate footage (thats the background footage on which you will lay everything) on the first track (1a for Premiere)

7. Put the mask you just created on track 2 and change the transparency settings for this clip to "track matte".

8. Place your original greenscreen clip On track 3. Change the Hue so the clip is relatively close to the same color as your plate footage. This goes a long way towards eliminating a white or black line around your composited image. You can also play around with the opacity settings. Change the transparency to track matte.

9. Put your original greenscreen clip on track 4, and change the opacity of this clip to around 70%. You may have to adjust the saturation to add a little color back into to image. Again, change the transparency to track matte.

10. Render your image (go get a beer and come back later).

Sounds like a lot of work, but the results are worth it. No more fuzzy edges. No more green or blue tinted composits. Crisp, clear images. Who needs Ultimatte!

Cheers,
slakrboy
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Old September 23rd, 2003, 06:49 PM   #43
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Thanks Mark. That does sound like a lot of work, but I'll try it... I'm just across the river in STL by the way.

Also your advice should suit me well since I'm also in Premiere. Thanks.
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Old September 24th, 2003, 07:25 AM   #44
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Glad to be of service. BTW, I get just as good results with this technique as I do with AE 5.5, and it's actually not that hard once you do it a few times. You can use this technique with any solid colored background, but you'll have to clean the matte up a little (or use multiple mattes). I do lots of sports video's, and I can usually pull a decent matte out of most footage.

Cheers,
Mark
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Old September 24th, 2003, 10:06 AM   #45
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We had been getting good chroma keys using Ultimatte, but recently we started playing around with the keying in Boris, and in most cases it gives us perfect keys, better than Ultimatte.
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