Oil painting is a form of painting that originated in the west, and is usually painted on canvas with oily pigments. In oil painting, signature and seal are not common practices. Although some painters may choose to sign on the back of canvas or drawing board to show the ownership and creation time of their works, there is no fixed rule or tradition.

In some cases, artists may use special signature methods on paintings, such as codes, symbols or patterns composed of letters or numbers, to express their artistic style or personal signs. These signatures are usually related to the theme, style or skill of the painting, but not every painter will use them.