My stock of illustration board was running dangerously low when, serendipitously, my habitual art supplier announced their annual "huge board sale." It took me a considerable amount of time to find an illustration board that didn't warp or buckle under the application of acrylic washes, and for that matter watercolors of any opacity, before I discovered Strathmore 500 series illustration board. This stuff is great for any dry medium as well as any paint cut with water, spray fixatives and clear mediums, and various applications (thick and thin) of gesso. It can even take oil pastels and fast drying alkyds without warping. Overall the Strathmore 500 series is a solid line of board, but for my individual needs, I prefer the Heavyweight Vellum 72pt variety. With both sides of the board coated with 100% cotton fiber 500 series drawing paper, it also provides a nice tooth for creating texture (this is also the secret to the warp resistance). On top of all of this, every piece of 500 series board is individually inspected ensuring only supreme quality in the boards available for purchase. I recommend investing in a 10 pack from Utrecht before the sale ends!