Referring to human relations, my father advised me always to "save the surface," which is something like "don’t burn your bridges," only more subtle. The connection between the homilies becomes literal in the paint industry: You must save the surface of an iron bridge to avoid burning or corroding its basic structure. Color is a distinctly secondary objective to structural preservation in the painting of such things as bridges, water towers, and battleships. Sometimes, however, the means to the objectives agree: In the case of the Golden Gate Bridge, the red primer retarded rust, was visible to aircraft through fog, and was much more aesthetically pleasing than the U.S. Navy’s alternative coloration of yellow and black stripes. So red was the chosen color.Sometimes color technology—which is based on the interaction of lights, pigments and human vision—also helps in the quality control of a paint job: Additives to the paint can accentuate the visibility of flaws and predict future corrosion sites. This approach helped solve a problem faced by the Navy. Aboard ocean-going ships, tanks that hold drinking water or ballast are vulnerable to slow breaches caused by corrosion that starts where paint covers the inside of the tank imperfectly.

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