Today we received a sample of Rosco grey rear projection screen, which one of my project mates from Holland sent me (thanks Martin). We wanted to test it, because the plastic white paper material we used as a projection screen didn't block any ambient infrared light and we knew Rosco did. But we wanted to know if the Rosco had a good coupling with the silicone rubber sheet.
The left blob on the screen is with rough surface down (on top of the silicone rubber), the blob in the middle is on the bare silicone rubber (without projection material) and the blob on the right is with the rough surface up (on top of the silicone rubber). As you can see the bare silicone rubber works the best (as aspected), but the goal was to see if the silicone rubber sheet would work with the Rosco rear projection screen. The blob on the right is a bit brighter then to other one, so we definitely want the rough surface up. The blob, with the projectionscreen with the rough surface down is also slowly getting more vague over time.
So probably the next step will be to order a layer piece of Rosco rear projection screen, so we can apply it to our box.