PEPINÂ« ArtistsÃ† Colouring Books contain 16 sheets of superior acid-free drawing paper, printed with exceptional designs in very light lines. The printing is done in such a way that, depending on the techniques used, the original outline will be hardly visible after colouring. The 180 gsm drawing paper is made by one of the best paper mills in Europe and is suitable for a wide range of colouring applications, including pencil, crayon, pastel, felt marker, gouache, etc. Also watercolors and liquid inks can be used. These Books match the quality of the finest artistsÃ† pads. For best results use good quality coloring materials such as artists' watercolors or art markers such as Tombow markers.