Medium for extra-fine artist's water colours "White Nights" The gum Arabic water solution based medium is intended for the dilution of watercolours. Whole using it improves the brightness and spread of colours and increases their drying time. A shine may appear on the surface of a work after drying. The medium can be used either pure or diluted in water. Instruction: medium can be added to the water, which diluted the paint or in the paints before application to the paper or canvas.