Oil paint
The advantage of the slow-drying quality of oil paint is that an artist can develop a painting gradually. Earlier media such as egg tempera dried quickly, which prevented the artist from making changes or corrections. With oil-based paints, revising was comparatively easy. The disadvantage is that a painting might take months or years to finish, which might disappoint an anxious patron. Oil paints blend well with each other, making subtle variations of color possible as well as creating many details of light and shadow. Oil paints can be diluted with turpentine or other thinning agents, which artists take advantage to paint in layers.