PEPIN Marker Colouring Books contain 16 sheets of superior acid-free bleed proof paper, printed with exciting and intricate designs. The printing has been done in such a way that, depending on the techniques used, the original outline will hardly be visible after colouring. The 150 gsm paper is made to our specifications to be suitable for alcohol and non-alcohol based felt-tipped pens and all types of markers. Other techniques can also be used. Using paper from responsible sources that is acid-free, colourfast and age resistant, the coloured sheets can be framed and displayed without the risk of rapid deterioration provided that high-quality, colourfast markers have been used.