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Blue screen background for video replacement

Posted: Thu Nov 06, 2008 3:36 pm
by Charles L. Cotton
Okay, this is a bit over the top I suppose, but does anyone know anything about using either blue or green backgrounds in a studio set so the background can be replaced with other video? I know this technology has been around for several years, but I have no idea if it takes an MGM studio to do it, or can it be done on PCs now.

Chas.

Re: Blue screen background for video replacement

Posted: Thu Nov 06, 2008 3:38 pm
by pbwalker
It can be done, but on a Windows box I have no idea how. It's pretty easy on a Mac.

If I am not mistaken, Sony's Vegas can do it.

http://www.sonycreativesoftware.com/pro ... family.asp" onclick="window.open(this.href);return false;

Re: Blue screen background for video replacement

Posted: Thu Nov 06, 2008 3:48 pm
by Keith B
Yes, Sony's Vegas does do it, as well as many other video editing software packages. The official name is Chroma Key. I have Vegas, but would personally recommend Ulead Video Studio or Media Studio for ease of use. You can download trial versions of either one and try them out before buying it too! :thumbs2:

The website for their video products is http://www.ulead.com/products/runme.htm#video" onclick="window.open(this.href);return false;

Re: Blue screen background for video replacement

Posted: Thu Nov 06, 2008 4:16 pm
by Charles L. Cotton
Thanks for the tip guys. This just saved me a lot of work and some money as well. ;-)

The software you referenced allows the replacement of the background with video, but can it also be replaced with a photo? There are times when I'll need a video and times when I'll need a photo.

Thanks again,
Chas.

Re: Blue screen background for video replacement

Posted: Thu Nov 06, 2008 4:22 pm
by Keith B
Yes. You should be able to a photo in just like a still captured frame. In the software, it is called an 'Overlay' and you set the background transparency depending on the color.

If you are planning to do a LOT of editing, make sure it is a fairly new PC with a hefty processor and LOTS of memory and hard drive room. Video editing is process/memory hog. The Mac is better and faster at video, but the PC will do it, just be patient. Call me if ya get stuck!

Re: Blue screen background for video replacement

Posted: Thu Nov 06, 2008 9:11 pm
by Piney
Couple of tips for shooting with a chroma key background--

Be sure to light the background evenly. Changes in light levels can cause the chroma key system/software to misinterpret its hue. This can lead to uneven replacement of the bg color. Also try to have the subject (person or object) lit well and brighter than the bg. Oh.. and watch for the same or similar colors in the subject as they'll get replaced also.

Colored paper might be used- some trial and error may be needed. Chroma key colors are specific hues, usually a blue or green. One can also buy chroma key color paint. Markertek Video Supply on the Net should have a selection of quality backgrounds.

Re: Blue screen background for video replacement

Posted: Thu Nov 06, 2008 9:32 pm
by Charles L. Cotton
Piney wrote:Couple of tips for shooting with a chroma key background--

Be sure to light the background evenly. Changes in light levels can cause the chroma key system/software to misinterpret its hue. This can lead to uneven replacement of the bg color. Also try to have the subject (person or object) lit well and brighter than the bg. Oh.. and watch for the same or similar colors in the subject as they'll get replaced also.

Colored paper might be used- some trial and error may be needed. Chroma key colors are specific hues, usually a blue or green. One can also buy chroma key color paint. Markertek Video Supply on the Net should have a selection of quality backgrounds.
Thanks for the information and I'll look at the website.

Chas.

Re: Blue screen background for video replacement

Posted: Thu Nov 06, 2008 9:33 pm
by KD5NRH
Piney wrote:Colored paper might be used- some trial and error may be needed. Chroma key colors are specific hues, usually a blue or green. One can also buy chroma key color paint. Markertek Video Supply on the Net should have a selection of quality backgrounds.
I'm feeling a bit too lazy at the moment to go look, but Adorama should have seamless background paper in Chroma-Key blue or green. :biggrinjester:

If it's not listed in video supplies, it'll probably be in the photo stuff. If you're just doing headshot/commentator type stuff, it should be sufficient.

As was stated, throw lots of light on it, and the same type of light to keep the color even.

Re: Blue screen background for video replacement

Posted: Thu Nov 06, 2008 9:54 pm
by Charles L. Cotton
The expertise available here amazes me!! Thanks so much guys.

Chas.

Re: Blue screen background for video replacement

Posted: Thu Nov 06, 2008 10:03 pm
by CHLSteve
I prefer to use the drop cloth over paper for durability. B&H Photo/Video carries a full line of this kind of thing, including the frames to hold the backgrounds. As the other poster mentioned, it is a specific hue of green or blue, not just any green or blue.

Re: Blue screen background for video replacement

Posted: Thu Nov 06, 2008 10:19 pm
by Keith B
Since this is going to be post edited replacement, the color should not be as much of an issue as the even coloring and lighting as was mentioned earlier. The software will allow you to choose a color to remove, so the more even it is the better the transparency will become on that color. The lighting will be the main thing to make sure you are evenly lit with no facial shadows and to wash the backdrop evenly. :thumbs2:

Re: Blue screen background for video replacement

Posted: Thu Nov 06, 2008 11:13 pm
by jimlongley
Piney wrote:Be sure to light the background evenly. Changes in light levels can cause the chroma key system/software to misinterpret its hue. This can lead to uneven replacement of the bg color. Also try to have the subject (person or object) lit well and brighter than the bg. Oh.. and watch for the same or similar colors in the subject as they'll get replaced also.
ROFL! A bunch of years ago my late wife had a (cable access) TV show and the producer decided to try a chroma keyed background to display some of the subject matter she would be talking about. Worked well, except for the clothing she had on that matched the chroma and the uneven lighting in the little studio - which provided us with some very interesting effects.

I was the producer. :drool:

Re: Blue screen background for video replacement

Posted: Fri Nov 07, 2008 4:30 am
by KD5NRH
I seem to remember one of the TV meteorologists getting a tie and hanky set in Chroma-Key green just to play around with the producers. :mrgreen:

Re: Blue screen background for video replacement

Posted: Fri Nov 07, 2008 8:16 am
by Keith B
Yeah, what is funny looking is if you wear a check or stripe that is close to the colors and it 'disappears' in the video. Looks pretty weird! :eek6

The earlier versions of Chroma Key had a pretty wide spectrum on the color range, so saw not uncommon for anchors to have 'holes' in their clothing. The system has gotten better and the wardrobe folks have gotten smarter about what not to wear, but you still see it every now and then. :lol::

Re: Blue screen background for video replacement

Posted: Fri Nov 07, 2008 2:23 pm
by Charles L. Cotton
Should I use any special type of lighting? I'm not a photographer so my terminology will probably be wrong, but how about something like the lights photographers use that look like reflective umbrellas, or a light box with some type of filter to help prevent shadows?

Chas.