I don't us black felt, I found a a fade resistant paper at an art supply store, I use 3M spray adhesive to adhere it to the board behind the portrait. I didn't want the backing to fade if the portrait is in the sun after being purchased, and I wanted to save space within the frame. now that I am more secure in my skills I am going to switch from 1/4 inch to 1/8 inch baltic birch and that should make it much easier to frame.