When painting a window-less room dark, matte green, its surprising how dark it is. Lighting becomes and interesting issue. You need to provide the camera with even light on your green wall to give it as close as possible, one single shade of green for the computer to be able to remove the colour.
You also need to light your subject, otherwise they’ll will look too dark for the replacement background.
And you need to make sure the subject does not cast a shadow onto the green, otherwise you’re back to different shades.
Get your presenters to stand around 4-6 feet from the wall. Place two lights above them in a line parallel to the wall about the same distance from the wall as your subject. Then place another light (with a filter) about the same distance from the wall as the camera is, but off to one side.
“That’s all very well“, I hear you saying, “but if you put lights up near the ceiling, they’ll burn the tiles and set off the smoke detectors“.
And you’re quite right, imaginary, if slightly gruff teacher.
That’s where these babies come in:
These Hi-lights are low temperature Halogen lights. Even when they’ve been running for an hour, you can put your hand on the casing and they don’t feel hot.
We got them from Newland Media, a company specialising in school video production. Newland also make/sell the brackets which easily clip onto ceiling tiles, which means you don’t need expensive lighting bars either.
The third light in our setup is a Tri-light. This does get hot! Very hot, so keep students away from it.
The enormous umbrella on the front is the diffuser (which comes with the light).
The whole setup costs near £1000 and is the most expensive area I’ll talk about, but the level of control you gain by lighting properly makes the investment worth it.