Arto Professional Watercolour Paper: Manufactured from high quality 100% cotton fibres this off-white, 300gsm, professional quality paper is acid free, non-aging and pH neutral. The surface of this paper has undergone a proprietary gelatin sizing process that delivers extraordinarily brilliant colours. Ideal for all classic watercolour techniques such as wet-on-wet, blending, dry brushing etc. A truly exceptional watercolour paper. Best suited for experienced watercolourists as its unique surface treatment makes corrections more demanding than with regular watercolour papers. Cold Press.