Paper of this sketch pad works beautifully with a range of marker types, specifically for alcohol-based markers. It is intentionally not completely bleed-proof. As an artist lays down marker strokes, the colour slowly sinks into the sheet. This allows the artist to move the ink around, blend, and pick up colour if needed. It will take around 13-15 layers of marker before the colour soaks through to the other side of the sheet. The 400 Series Marker paper is a bright white sheet, acid-free, and does not contain any Optical Brighteners.