With a clamshell design, the 13 x 19 x 1.4" Onyx Portfolio Box from Archival Methods flips open to allow easy access to your prints. The interior of the box is lined with an 80 lb acid- and lignin-free black paper. With a depth of 1.4", the clamshell box can accommodate 14x 4/2 ply, 10x 4/4 ply, and 20x 2/2 ply matted prints. The adhesive used in construction is pH balanced, and the archival box has passed the Photographic Activity Test (PAT), which makes the box suitable for long-term storage.
The box core is made from a 0.100 Kappa Binder's Board, which is lignin- and acid-free, and the sulfur content has been reduced to <0.0008%. The board has been buffered to keep acidity from transferring to the stored materials. Furthermore, the exterior of the box is bound in a library quality F-Grade Buckram (poly-cotton), which is coated in a moisture-resistant, 100% aqueous acrylic.