PEPIN(R) Postcard Colouring Books contain 20 postcards (format 10 x 15 cm, 4 x 6 in) of superior 250gsm acid-free and age resistant drawing paper, printed with 20 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 first-rate paper is made to our specifications 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 water colours and liquid inks can be used.