Oil painting is the process of painting with pigments that are bound with a medium of drying oil. Commonly used drying oils include linseed oil, poppy seed oil, walnut oil, and safflower oil. Different oils confer various properties to the oil paint, such as less yellowing or different drying times. Certain differences are also visible in the sheen of the paints depending on the oil. An artist might use several different oils in the same painting depending on specific pigments and effects desired. The paints themselves also develop a particular consistency depending on the medium. The oil may be boiled with a resin, such as pine resin or frankincense to create a varnish; often prized for its body and gloss.