Golden Gate At Dusk International Orange

Construction on the "most photographed bridge in the world", the Golden Gate Bridge, began in earnest in January of 1933 but the wrangling over issues such as funding, engineering design along with the political opposition lasted for almost 18 years prior to the bridge being completed on May 27, 1937. A bridge across this stretch of the Golden Gate Strait was essential to connect Highway 101 to Marin County and to connect the coastline between southern and northern California. The civil and structural engineering design required to build a span across this portion of the Strait was considered by many to be "a bridge that could not be built". Though never really getting full credit for the design until 2007, the principal engineer for the bridge was Charles A. Ellis in collaboration with Leon Moisseiff, a New York suspension bridge designer. So after many years of haggling over funding and despite the Great Depression of 1929, the citizens of six northern counties of California voted to finance the bridge. In 1971 the last of the original $35 million construction bonds was retired.

A few fun facts: the twin towers reach to a height of 746 feet above the sea level with the pavement at 220 feet above the water. There are over 1.2 million rivets and over 80,000 miles of wire in the two main strand cables. Until 1964, the main span was the world's longest suspension bridge at 4,200 feet.

While this blog could go on and on for pages about the bridges finer details, it will instead concentrate on the paint color of the San Francisco bridge:

The paint color for the Art Deco style bridge was studied, analyzed and finally decided through a lengthy process between city officials, sculptors, artists, the military, engineers and architects. The color was not decided until 1935, just 18 months before the bridge's completion. The primary consulting architect of the bridge, Irving F. Morrow, made the push for the final color in his 29-page document called "Report on Color and Lighting" presented to the bridge's Board of Directors. But the permitting agency, The Department of War, also had to be convinced to paint this wild and crazy color. The U.S. Navy wanted to originally paint the bridge black with yellow strips to ensure visibility ! Morrow felt the vermillion orange that was used initially for the steel corrosion sealer, a shade variation of international orange, complemented the natural surroundings and enhanced visibility in the fog as well. While the wild color is a form of international orange it has enough of a shade variation to actually be unique onto itself. In 1937, over 10 million square feet of steel on the bridge was painted. Painting Golden Gate is done daily, but not from one end to another as most people think, rather it is touch-up paint maintenance issue, ongoing year after year, to stop the corrosion inherent with salt air. In 1968, the painting program changed from touch-up painting to removing the original lead-based paint and replacing it with an inorganic zinc silicate primer with a vinyl topcoat. However, in 1995 the vinyl was replaced with acrylic emulsions due to the concerns of high VOC's (volatile organic compounds). International orange is a color widely used in the aerospace industry and by the U.S. military, though shades can vary. 

See this link for details about international orange: http://en.wikipedia.org/wiki/International_orange

This photo was taken at the lookout point called Battery Spencer, a former military overlook in Marin County expressly installed to protect the bridge and the strait during WWII. The photograph: Nikon D800, with 28-70mm lens focused to 44mm on a tripod, 1/50th at f/14, pushed to ISO 400.