Green Screen, Blue Screen, Chroma Key

greenspun.com : LUSENET : Shooting DV Films : One Thread

I am looking for any information about TRV900 DV shooting in front of blue or green screen for chroma key in post. Any suggestions on low budget solutions such as:

1. how to make your own portable blue or green screen? 2. how to use lights for this type of shooting? 3. where to buy this materials?

Thanks in advance.

-- Vasily Shumov (vasily@newmediaman.com), August 03, 1999

Answers

I have worked with blue screening and green screening for 2 years and I hav found that green screening is the way to go. There are too many costumes that people wear that have blue in them. And unless you have an excellent chroma key you can't take out all the blue. I just made a portable green screen, 16' long for under $200. You need to buy 8'X4' wood paneling, and paint the smooth side. Frame it in with 2X4 and you have a green screen. With the one that I made we made it double sided. So if you only use one side then it will be cheaper for you. It was also self supporting. Hope that helped.

Erik Ludwig

-- Erik Ludwig (eel8099@yahoo.com), August 04, 1999.


I just spent a total of $30 on flourescent green and blue cotton fabric and it yields pretty good chroma keying. I matched the color with a pantone swatch book from actual ultimatte colors and just went shopping until I found a close enough match. I use a steamer to get wrinkles out on location or on set and then I stretch the fabric gently between two C-stands weighted down with sandbags. The fabric is 50 inches wide X 12 yards long and I bought 2 panels of each color. Very inexpensive, portable, and easy to use. I key the footage in premiere 5.1 on a G3 Mac and shoot with either a VX-1000 or TRV-900. Hope this helps.

John Brune

http://www.geocities.com/~steadicamjr

-- John Brune (jbfine@fortwayne.infi.net), March 15, 2000.


Ha, I beat you all. I spent 59 cents at Walmart and bought flourecent Green poster board. Well actually I bought 9 of them, and some green thumbtacks, and put them up on my wall. I filmed it with my 50 dollar video conference camera, and also my Canon GL-1 camera. Make sure it is evenly lit, and you don't stand to close. I used After Effects to chroma key it, but you could use Premiere, or if it is not to long, use photoshop,,,, frame by frame.

Other ways, keep a eye on the sky, last week I noticed the sky was almost pure blue, so I filmed some hills and trees and took it back to my lab, sure enough, I was able to make the blue sky anything I wanted. If you don't have a lot of money, than just be creative. You might have to work a little harder, but you can achieve professional results.

I just ordered a green screen 6X7 from a flim company,,,it cost 200 bucks. But this is because I need to do outside shots, and have more time working on other special effects than setting up poster board. The sun works great for a light source. But bring a something reflective to light your objects dark sides.

I might be wrong, but I am finding out that de-interlacing my DV footage works well, and saving it as a uncompressed avi before I work with my files, and I heard green screen works better for DV.

But I am learning more each day. Hope this helps, and please email me any new tips you guys find. Jeff Lampo

-- Jeff (jlampo@ravensoft.com), May 10, 2000.


i Agree With John i Did the same thing with the poster board and thumbtacks. I m only sixteen So i have a really low budget(none) i HAve found that i ca make pretty damn good looking movies with this technique and a regular RCA Proview. I enjoy making movies with a few of my friends and the special effects are pretty cool for what i have.

-- kevin kramer (kevhands84@hotmail.com), June 04, 2001.

Likewise, the cheaper the better. I've tried a few different methods now and found that poster board was a pain cause the seams would create a darker area of green and therefore an inconsistant color. I'll be ordering a gal. of Roscoe green and painting a board now for future use.

But hey, whatever works right...

-- N (ngreene@foomanchew.com), August 06, 2001.



Green screen good. Blue screen bad. I've been a visual effects artist for 10 years and I have found that blue always more problematic than green in most cases. Now obviously if you have any green in the wardrobe or item your shooting you'll have to use blue. Also depending on what type of keying software you have blonde haired subjects in front of green can get, well hairy. I would not recommend any seems or folds in the chroma key material. Try to space you subjects as far from the screens as possible without breaking frame. Even lighting on the screen is crucial. If you have reactive lighting on the subject( fire/water/etc.) try to keep that from casting shadows or effect the lighting on your screen. Also, just because you can pull a good matte doesn't mean you will illiminate spill from the color of screen you use. Spill light is a color cast on your subject caused from the screen behind. Again as much seperation of screen and subject can eliminate alot of this.

Be careful with highly reflective props and wardrobe. Otherwise you will end up rotoscoping or garbage matting alot of frames. You can buy dulling spray from most production rental companies. They also have chroma key colored gaffers tape. A roll of this comes in handy for masking off stuff quickly.

Once you've wrapped up shooting and start pulling mattes on your pc,avid,inferno,photoshop you may encounter more problems due to format or just missed something in the eye piece while shooting. Don't panic. Sometimes it isn't one good matte for the job. You may have to take several passes at the shot and key specific areas at one time. Than you can combine all of the mattes to make a perfect chroma key. Alot of software has the ability to color correct certain colors to help remove a green or blue cast.

No chroma key shoot is the same. Sometimes you have no trouble and than there are the times where your pulling your hair out.

In response to making a portable chroma key screen it is necessary to know how large of an area you need to shoot. If you use fabric make sure it is secure at all corners especially if shooting outdoors. To manufacture a light weight large screen it might be best to look at rental costs before purchasing materials to build. Alot of equipment rental shops have green and blue screens of all sorts of sizes.

Hope this helped. Good luck.

-- trent shumway (trentandmissy@aol.com), July 26, 2003.


Moderation questions? read the FAQ