White Core matboards combine the aesthetic and design benefits of a striking, bright white bevel with the affordability of regular matboard. The premium white core stays white through an equivalent 100 years of accelerated aging, as verified by independent laboratory testing. White Core is best suited for decorative, non-conservation framing of reproductions, posters, and graphics. The core, surface, and backing papers are buffered, pH neutral wood pulp. 4-ply, .055" thick.