Green screen - can I paint one?

[Brian Manning]

Hi,

I just moved into a big new office. Its an old art room, big and roomy. I was going to have a green screen area against one wall. My question is would it work if I painted the wall(and floor?) the colour green I desired?
Also, when is a blue screen used?

Thanks,

B

[Chris Medico]

You could us about any color you want but your best performance will be from the correct shades of blue or green.

I did a quick search and found several companies offering the chroma key paint in blue and green.

The choice to use blue or green is dependent on the color content of what you are trying to key.

As an example you would use blue if you were trying to key Kermit the frog. ;)

If you do go with an off the shelf paint be sure to get the flattest finish available.

[Arnie Schlissel]

Rosco and a few other companies make chroma key paint in both blue and green. It's expensive, but you know it's the right color.

If you have a swatch of blue or green screen paper or fabric that you know works well for you, then you can take that to any store that custom mixes paint and have it matched. That will be cheaper, and you'll have the comfort of knowing that you can get it locally when you need it.

As for when blue is used instead of green- you use it anytime that green is problematic. The phrase "blonde on blue" is very true.

[Pete Bauer]

It's from 2007/2008, but also take a look at this thread:
http://www.dvinfo.net/forum/digital-...ome-depot.html

[Robert Turchick]

Just built a 12' wide, 9'tall with a 9' floor screen in my new space. I used Kiltz ultra primer white as a base. One gallon of Rosco has put down 2 coats on the wall and 3 on the floor. (already done 4 shoots so the floor had some scuffs and needed the extra coat)
The Rosco dries very quickly and covers better than any paint I've ever seen.

As for expense, it's really not any more than super premium paint which has a purpose...goes on with fewer coats and is exactly the right color from batch to batch.

Brian, you say you want to do a floor and wall...are you planning on building a cyclorama? Or at least the transition from wall to floor?
Don't leave it a hard corner or any full body shots will be next to impossible to key out the line.

Check out the pics on my site listed below...

[Dom Stevenson]

You can get away with cheap and cheerful paint from a hardware store if you know the correct shade. Good lighting is the key to success (scuse the pun) and shooting with a camera with decent colour sampling is advisable. Cant see much point in paying for expensive paint myself, but others may disagree.

[Jim Andrada]

The "expensive paint" is pretty cheap when you think how little you really need. The purer/more accurate/more consistent the paint, the better. It's nicer if the shade of green is further away from someone's green eyes unless you're doing a horror movie.

[David Barnett]

I think originally TV used blue but when alot of weathermen had blue eyes or ties it caused chroma keying problems. Hence the switch to neon green. As Chris said you can use any color you want, just use an eyedropper to grab what color you want out, but ideally you'll go with something abstract & non in someones facial or hair/eyes features. (Red orange etc can match skin tones, white & black likely matches clothing etc..)

[Pete Bauer]

It gets technical well beyond my knowledge, but my understanding is that the use of green for video keying has to do with the chroma subsampling. The cleanest key can be pulled from the green channel due to the chroma sub-sampling. If possible, you want to use the "4" in 4:1:1 or 4:2:0 or 4:2:2 rather than a "1" or "2."

[Jim Andrada]

Come to think of it that's probably true - I used to hear things like "Blue for film, Green for video" tossed about.

And the more I think of it that's probably why the real chroma key paints are the specific color they are - ie GREEN and not green mixed with a bit of red and a splash of blue.which most casual observers (or hardware stores) would still call green

[David Aronson]

Chroma keying was originally done with blue because there is (almost) no blue in human skin tone and that was needed to preform the key. It was originally done with a complicated system of negatives and optical printers (film stuff). Green caught on when video started getting popular since video cameras are more sensitive to green light and have a higher resolution in the green channel. Human eyes are also most sensitive to green so they picked green to have the highest resolution on cameras. Green caught on in film when digital compositing became popular. Studio owners were also happy because they didn't have to repaint their cyc when switching in-between film and video. Green also reflects more light than blue so you can use fewer lights and achieve a higher luminosity than you could with blue.

[Shawn McCalip]

The color green is carried along with the luminance signal, which is another reason why it's better to use. Blue is the most heavily compressed color out of the 3 channels, so while it can work nicely, green is a bit easier for pulling a good key. As for using inexpensive paint from Home Depot or Lowe's, you certainly can use them. Like others have mentioned, those expensive chroma green paints are mixed for color accuracy and consistency. They're also extremely flat so you can light them properly. Inexpensive paints have a glossy or satin/eggshell finish, and that causes hot spots and glare. One way around that is to mix in a few cups of fine sand into the cheap paint before painting. The sand creates a texture that will appear smooth from a distance, but reduces the glare and hot spots that you would get if you just used cheap paint all by itself.

[Oyana Beasley]

Another option is go with Green Screen Seamless paper. It works very well.

Director Of Post Production
KAR STUDIOS, LLC
www.karstudios.com

[Earl Thurston]

One of the other reasons blue was used for film visual effects was that the high-contrast stock used for creating traveling mattes was mostly blue-sensitive (orthochromatic).