St Cuthberts Botanical Ultra Smooth is a 300gsm paper which is mould made from 50% cotton, and which is suitable for use with watercolours, watercolour pencils and acrylics (as well as many dry media). It is acid free and calcium carbonate buffered. The absence of acid guarantees excellent permanence and resistance to ageing. The colour (High White) is a very close match to Fabriano 5, and it does contain optical brighteners to give it a bright white colour. It is ideal for botanical watercolour painting as well as charcoal, pastels and graphite.