Golden Gate Bridge, Highway & Transportation District

Why the International Orange Color?

What is the Color Formula?

Click here to listen to Kevin Starr talk about Golden Gate Bridge Consulting Architect Irving Morrow’s selection of the International Orange color.

When the steel for the Golden Gate Bridge was fabricated by Bethlehem Steel at its foundries in PA and NJ, the steel was coated with a red lead primer. As the bridge towers began to rise for the Golden Gate Bridge, consulting architect Irving F. Morrow was commuting to the construction site from his home in the East Bay via ferry. He became inspired by the red lead color. Morrow undertook color studies, which resulted in the specification of the unique Golden Gate Bridge International Orange because it blended well with the nearby hills and contrasted with the ocean and sky.

Morrow recognized very clearly that the Bridge color was a very important influence on its appearance in relationship to its surroundings. As the Bridge stands today, the color blends perfectly with the changing season tints of the spans’ natural setting against the San Francisco skyline and the Marin hills. Morrow concluded, “The effect of International Orange is as highly pleasing as it is unusual in the realm of engineering.”

The color dubbed “International Orange” existed before the Bridge (and still exists) and is a color used in the aerospace industry to set things apart from their surroundings, similar to safety orange, but deeper and with a more reddish tone. You can see this, the “other” International Orange color here:

The Golden Gate Bridge is painted Golden Gate Bridge International Orange which was selected by Consulting Architect Irving F. Morrow.

In his April 1935 Report on Color and Lighting, Morrow defined the approach to the color section, “Preliminary to discussion of particular colors, a decision must be made on a matter of policy – is it desired to emphasize the bridge as an important feature of the landscape, or to make it as inconspicuous as possible.”

The final color was inspired by studies undertaken by Morrow in cooperation with other architects, engineers, painters, sculptors, and others. Morrow also included black, grey, and aluminum in the studies, ruling each out for a range of reasons. Black would be unattractive and would reduce the scale of the bridge more than any other color. Proponents for the aluminum color reported that this color would give beauty as the beauty of a dirigible aircraft. Morrow rejected it as the towers would be deprived of substance and made tiny. Battleship grey and warm grey were studied. Warm grey was named as the distant second to orange vermillion.

Italian American sculptor Beniamino Benvenuto Bufano submitted his comments to Morrow, “ I have been watching very closely the progress of the towers on the Golden Gate Bridge in its structural beauty its engineering and architectural simplicity – and of course its color that moves and molds itself into the great beauty and contours of the hill – let me hope that the color will remain the red terracotta because it adds to the structural grace and because it adds to the great beauty and the colorful symphony of the hills—and it is because of this structural simplicity that carries to you my message of admiration.”


Color Formula

The Golden Gate Bridge International Orange color is mixed to our requirements. The Bridge has maintained our formula for GGB International Orange through the years. Our requirements are in no way proprietary, anyone can formulate and use the color – in fact we provide the color percentages on the website. What passes for International Orange is going to vary by manufacturer or standard of which there are many. When purchasing paint for the Golden Gate Bridge, it is done through a competitive bidding process. Currently, the paint is supplied by Sherwin Williams and is made to match the GGB International Orange color formula. For compliance purposes we use ASTM D 2244 – Standard Practice for Calculation of Color Tolerances and Color Differences from Instrumentally Measured Color Coordinates.

When purchasing paint for the Golden Gate Bridge, it is done through a competitive bidding process. Currently, the paint is supplied by Sherwin Williams and is made to match the Bridge International Orange color formula. The closest off-the-shelf paint color that Sherwin Williams has available is "Fireweed" (color code SW 6328).

Many people ask about the formula for the Bridge’s unique International Orange paint color. Paint stores can mix it with the following information:

CMYK colors are: C= Cyan: 0%, M =Magenta: 69%, Y =Yellow: 100%, K = Black: 6%.

The closest existing color codes to GGB International Orange color are:
PMS 173 (CYMK = 0%, 80%, 94%, 1%),
PMS 174 (CYMK 8%, 85%, 100%, 34%)
Pantone 180 (CYMK 19.4%, 77.9%, 79.6%, 3.6%)