Originally Posted by ghostrider

Yes, the scrim has everything to do with it. With W&N and W&W, the scrim side should be next to the back of your quilt. It's the flatter, whiter side (even on W&W it's slightly whiter and definitely flatter). 'Bump it up' is what I've always used to remind me which way is up and it DOES make a difference on DSM's, at least for me...possibly because I usually have black backings.

When quilting with the scrim side down, you are duplicating the way the batting was needlepunched and the batting fibers remain secure in the scrim. With the scrim side up, you are actually 'unpunching' the batting fibers and pushing them through the backing fabric.