This 5 x 8" is part of our Fibonacci series - closely related to the Golden Mean proportion! Canvas Depth: 7/8", Canvas relief: 5/16" (Space between canvas and Bar). Belgian Linen, 11.3 oz. primed weight. Heavier weight and finer weave, double sized and double primed with an absorbent archival quality, grey tinted, alkyd oil primer; impervious to paints leaching. For for oils or alkyds only. Linen is the world's strongest natural fiber. It has oils that keep it flexible and prevent disintegration over time. The heavier weight and finer weave produce a smoother surface texture Solid Pine or Fir Stretcher Bars from the sustainable forests of the Pacific Northwest. No finger joints are allowed, which tend to fail under pressure and over time.