Hello. I see what happens when I don't get on here daily. ;^p
@Jeffrey Richardson , do you happen to know the specifics on your screens (manufacturer and model)? The issue is that white will reflect everything. In all honesty, I don't know why we keep using white for front projection. It was very necessary back in the day when a 500
lumen projector was "high brightness". You needed the ability to
return as much light as possible (and keep all unwanted light off). First thing I would try (if you can not put down carpet or something else to absorb some light) is to use your rear fabric, with black
masking immediately behind it, and use it for front projection. The grey may give you a better contrast allowing for the
image to appear better.
If that doesn't work, you may try taking your front projection
screen and invert it. It may have some ambient light rejecting properties. If you get really close to the
screen, you will likely see a texture to the surface. This texture is to better reflect the light to the audience, giving you known values for
gain (reflectivity) and viewing angle (angle from center to which the reflected brightness is halved). The texture may be created in such a way that it reflects part of the light away from where the audience is perceived to be (and where ambient light usually comes from, above). Since the light is being controlled from above, but not below, inverting your
screen may improve your
image.
In all honesty, your best bet is to reduce the size of your
image. I can see using the full
screen size if you are having a movie night of some sort, but as soon as you have presenters on
stage, you should have an
image at least 1/3 smaller. By zooming in, or using your rear
screen as intended, with the size that it creates, you will be concentrating your light and having it brighter. Bring in your blacks to mask the top and sides. If you can get some
pipe and drape, or
build a bottom
masking, that would be ideal. I have a 4:3
screen that I mask to be 16:9 instead of having unused space on the
screen.
Diffusion won't really help. It will take away some of the harshness of the
reflection, but you will still be getting ambient light pollution. However, the right diffusion might help your side lights do a better job of illuminating the subject, allowing you to bring down your front light even more. If, by side lights, you mean the two groups of three on either side of the
stage, they still seem to be fairly far away and will still be front lighting your subjects, just from a wider angle. If you are able to get a
boom on either side, that would provide better side light.