Here is a quick response to a question a reader asked the other day about how to green screen. He wondered how far the on-camera person should be from the green background. He said he was very frustrated because he had searched for an answer and everyone said something different. There was no consensus, so he was confused. Who wouldn’t be?
I explained the reason why no one seemed to agree is that the proper distance between the background and the on-camera talent is entirely dependent on the particular situation under which you are videotaping. So there is no one right answer.
On a strictly technical level, the distance is totally irrelevant. What matters is that the green background is an even color. No variations. Shadows or hot spots are the chief problems that cause variations in color. The darker color of the shadow will cause the green screen effect to be uneven. The hot spots will be too bright, so those portions of the background will look like a completely different color to the computer trying to get the mix right.
If the on-camera person is standing very close to the background, chances are her shadow will fall on the background. But if the on-camera person were twenty feet from the background, the same shadow would fall harmlessly on the floor, which is cropped out of the picture.
Problem is, most people do not have the luxury of that much room.
In an ideal situation, most professional videographers would place the on-camera talent at least five or ten feet from the background. This gives the talent a little breathing room and helps ensure an evenly lit background.
However, when I took a tour of ABC News studios in New York, I saw them videotape a news update and the anchor person was smashed up against the wall. They shot the news update from her office, which was tiny. It looked great on the air. I could barely tell it was a green screen. It looked real!
The lighting in her office was extremely diffused, so there were no shadows. The green behind her was homogenous, so it gave a beautiful green screen effect.
So if you have some room to play with, go for a distance of about ten feet. If you don’t have the room, do not worry about it. Just make sure your lighting is diffused, so the shadows will be minimal or non-existent.
Lorraine Grula
FOOD FOR THOUGHT
- Why is there no one single answer to the reader’s question about how far the on-camera talent should be from the green background?
- Why do shadows and hot spots cause problems when you are trying to do the green screen (chroma key) effect?
- What kind of lighting will help overcome those problems?