Mike Earussi , May 10, 2006; 08:57 a.m.
All black backgrounds will reflect light to some extent as there is no such thing as a material that is 100% absorptive. The best is the black felt material that photo stores sell, but it is very expensive and flakes very easily.
I setteled on black material from a material store and then try to keep light off of it as much as possible. The material I found comes in 102" width and since I needed it for a wide background, I used iron on glue tape to glue two pieces together. Even though it cost me around $80 that's still a lot cheaper that the hundreds it would have cost for the offical photo black material, and it's a lot tougher too.
As for location, only the larger material stores tend to carry such wide widths. Just look in the Yellow Pages and call around.
Good luck. Mike