Metal articles having a durable visible marking on a smooth Type III hard anodized
surface particularly useful for shock absorber tubes are produced by applying an
alkaline solution to the anodized surface for not less than about 15 seconds at
temperature of 100-140 F.; applying a pattern of lacquer based solvent
ink to said surface; and sealing the applied pattern by applying a liquid selected
from the group consisting of nickel acetate, cobalt acetate and boiling water to
said pattern.
