Is this Blackout Cloth?

[Mr.Kh]

It looks like blackout cloth to me:
One side should be rubbery(yours looks grey to me)(30%polyester)
One side should be woven with a bit of a grid like canvas, and should feel like cotton pants.(70% cotton)

I can see the screen door effect because I have XGA resolution at a huge size.

I cannot see the grid on the cloth, it's far too fine.

My polyester side is white (both sides are). The poly side gives a better brightness, I've foled it up so part of the projection is on the cotton side and part is on the poly side.

With regard to calling it blackout cloth, since you bought it at a cloth store, they're probably not too concerned about making sure you know it's cloth, seeing as that's mostly what they sell.

You have something very similar to what I have, the polyester side of yours just appears to be a different color than mine.