Fredrix Archival Linen Boards These New Professional Grade Canvas Boards are constructed throughout with the highest quality, non-acidic archival materials. The hardboard core will not warp or rot. Mounted with acid-free adhesive, 100% Belgian linen used on our finest pre-stretched canvas. Grounded with a proprietary, two coat, acid-free formula of acrylic-titanium gesso primer, these Professional Grade Painting Supports are truly archival. They are suitable for oil or acrylic painting. Best of all, they carry the Fredrix Archival Seal of Quality—your assurance that this product is indeed archival and will stand the test of time.