In matting, ply refers to the thickness of the mat board. Each “ply” is a layered sheet of paperboard—so the higher the ply count, the thicker and more substantial the mat.
4ply Overmat
The standard thickness, offering a clean, refined border that subtly frames the artwork without drawing too much attention.
8ply Overmat
Noticeably thicker, creating a deeper bevel and more pronounced edge that adds dimension, shadow, and a more elevated, gallery-style presentation.