Adding Winsor & Newton Gum Arabic to watercolour paints has three effects: It slows down the drying time of the paint, giving slightly longer to work on creating an image or working wet into wet. It adds further transparency to watercolours and it increases gloss. Gum Arabic washes will have greater depth and appear more luminous than colour washes alone. Gum Arabic is typically mixed directly into watercolour washes but can also be added to a jar of water if it will be used throughout a painting. Gum Arabic should not be used directly from the bottle because any thick films created will become brittle.