Stillman & Birn Nova Series - Wirebound Sketchbook - Portrait 9 x 12 - 150gsm Black PaperHEAVYWEIGHT PAPER: Strong enough to use wet media on both sides of page. Example usage: ink underdrawing followed by layers of gouache. MIXED MEDIA TONED PAPER: Double sized for enhanced wet strength, yields high contrast and glowing color on toned paper. ERASABLE & TOUGH: Withstands multiple erasures and holds up well to layered light washes of wet media. DURABLE: Thick board, premium U. S. coil binding, and heavy duty art paper equals a sketchbook