no lights in the room is ok, but i'm not talking about that;
i'm talking about corrupting the shadows on the screen and diminishing contrast in the images.
Explanations and examples:
Supposition 1: your wall on the side is a shiny white.
when you project an image on the screen, light will spill to the wall on the side; as the side wall is very shiny, that light will reflect back to the screen and will degrade contrast and give an overall haze effect to the image. same thing as if you were to put a light on in the room.
Supposition 2: your wall on the side is a nice green.
when you project an image on the screen, light will spill to the wall on the side; it will be strongly tainted by the green color of the wall and then will be reflected back to the screen.
you will then perceive that your images on the screen will have a distinct green overcast, in spite of the fact that your projector has been calibrated by an expert. shadows will now be green too, and not very dark.
my recommendation:
paint both side walls a neutral gray, not very light and not very dark and also the ceiling.
you only have to paint those surfaces starting a couple of inches back from the screen, right up to where you're sitting.
the paint must be matte or nearly so, to absorb the light even more.
the gray should be very acceptable - remember it was the fashion some years ago to have gray painted walls, and i think it looked very good.
if you do that, i can guarantee you will have images on your screen as good as the projector is well calibrated, the room will have no bad effect on the quality of the images.
hope this helps. :-)
