These were beautiful out of the box.  They blocked out at least 90 of light.  But I washed them once in cold water and hung them up to dry to get the wrinkles out and the foam backing on one of the curtains sort of bubbled up in a few spots, separating from the fabric. It is only noticeable when the curtains are drawn in bright sunlight.  But it makes me hesitant to wash these again. 

They do a great job of blocking the sun though and even do a great job lowering the temp in the room.