Bluing (steel) Bluing is a passivation process in which steel is partially protected against rust using a black oxide coating. It is named after the blue-black appearance of the resulting protective finish. Bluing involves an electrochemical conversion coati ...

is a passivation process in which steel is partially protected against rust Bluing may also refer to: * Bluing (fabric), a blue dye used to improve the appearance of fabrics *

Bluing (hair) A blue rinse is a dilute hair dye used to reduce the yellowed appearance of grey or white hair. The blue rinse gained popularity after Jean Harlow's appearance in the 1930 film '' Hell's Angels''. Queen Elizabeth The Queen Mother Eliz ...

, a blue dye used to improve the appearance of hair * "bluing" of machine parts to check for tolerances, see

engineer's blue Engineer's blue (also known as scraping blue, Prussian blue, or simply bluing) is a highly pigmented paste used to assist in the mating of two or more components. History Joseph Whitworth popularized the first practical method of making accurat ...

See also