I call the whole package going into a frame a 'sandwich'. Not sure if that's just me, or if I picked it up somewhere. Our sandwich for an average Limited Edition Print looks like this: Bainbridge Artcare AF Foam backing (because of its zeolite quality, we use it right to the art) Print (held with corner mounts, to keep it removable) Matting (held to the AF foam with a little ATG) Glass We'll often tape from the edge of the glass, around the edge of everything, to the back of the foam, using clear plastic packaging tape to help keep flakes from entering between the glass over time. What does YOUR 'sandwich' look like? I've read some prefer using a few dots of white glue to replace the ATG. Thoughts? I'm always looking to learn and improve.