Join Date: Dec 2001
Location: Redondo Beach, California
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The UM-200 and Videomatte are pretty similar in gain, but UM-200 is available in larger sizes. Videomatte, years ago had a gain factor of 2.2 but we lowered the gain as projectors improved.
As far as relative performance in ambient light, the higher gain fabrics will get you brighter rendition at the top of the dynamic range, so yes to a degree, the dark areas of image content are relatively darker. The difference is no where near the difference when a neutral density gray screen is used.
Remember that in ambient light, the cumulative light falling on the screen surface, from openings, or from cross reflected projection light, is the color black as you will see it, for all intents and purposes. Look at the screen as the projector warms up or in a fade to black, that is your system "black".
In high ambient light it will be a white color or muted non reflective white. Then we add collimated projected light above that level, to whatever level the output of the projector allows, of course multiplied by the relative gain factor. With a bright projector, you can get some dynamic range from "black"(actually dull white) to white, (brilliantly illuminated screen surface). But with a gray screen you get way blacker from the bottom of the range, and if the material is engineered to respond to collimated projected light, and is less responsive to light coming from less perpendicular angles, then black is much deeper.
The trade off is at the top of the dynamic range. It is possible to overhaul the gray tint of a screen with projected light power and get a calibrated white field. People argue this to death. It is done. A sample pasted on a whiter wall is not indicative of the performance of the screen, since cross reflection from the base material is still washing everything out. And granted you must have a more powerful projector to light a Grayhawk RS, than what is needed for a given foot Lambert performace level with a white screen. But if proper set-up is followed, an accurate picture is obtainable with either.
Firehawk is pretty good at rendering a believable white and providing blacks where other fabrics just cannot. It not as textbook white field accurate, but it makes projectors with reduced black level performance look much better, and salvages many rooms which otherwise wash out to unacceptable degrees. Images are believable and that is why people create Home Theatres.
Naturally it would be wonderful if all viewing environments were black floored, had black ceilings and walls, and so forth. It would also be nice if digital engines could acutally render a black field where IRE=0 was pitch black, few to none can. Gray screens help with both of these issues.
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