Painted on Yasotomo mineral paper. “What’s mineral paper,” you say? Glad you asked! Yasutomo Mineral Paper is crafted from calcium carbonate gathered from rocks instead of tree pulp like traditional based paper. This makes Mineral Paper an environmentally friendly alternative. Composed of 80% calcium carbonate and bonded together with a small amount of HDPE (plastic); Mineral Paper has very unique qualities such as tear and water resistance and it will not bleed through even when soaked. It is also an acid free product, which is desired for works of art.