From J.V. Howe (of Griffin & Howe), Formula No. 27, a GRAY color on steel is achieved by immersing the work in a heated solution of:
10 gr. (avoir.) Antimony Chlorid
10 gr. gallic acid
400 gr. ferric chlorid
150 cc. distilled water
The first color to appear is pale blue, then darker blues to purple, and finally to gray. If immersed long enough the metal will assume the gray color.The intermediate colors are better produced when the solution is cold. The above is considered one of the "bronzing solutions."
