What makes Chelsea porcelain marks useful for dating?

Chelsea used a list of marks that many museum records associate with time periods, early incised triangular marks around 1745–1749, raised anchors around 1750–1752, red anchors around 1753–1758, and gold anchors around 1759–1772. This sequence provides a working timeline of marked pieces, which is rare among early English porcelain makers. Later copies exist, so match the style of the mark to the object's paste, glaze, and decoration. A 1750s-style red anchor on a plate painted in the later Derby pattern may signal problems. For more accurate dating, combine examination of the marks with a close match to a published Chelsea form held by the museum.