The 13-cent Washington State Flag stamp (Scott 1674) depicts the state flag adopted in 1923, more than thirty years after Washington was admitted to the Union.
Olympia, Washington, jeweler Charles Talcott first designed the flag in 1889. He used an ink bottle and a silver dollar to draw the rings of the seal and then pasted a postage stamp in the center for the picture of George Washington. His brother L. Grant Talcott lettered the words "The Seal of the State of Washington 1889." Another brother, George N. Talcott, cut the printing dye from a color drawing of George Washington that appeared on packing box of 'Dr. D. Jaynes Cure for Coughs & Colds' when, under magnification, the postage stamp proved poorly detailed.
The flag is dark green with a reproduction of the Washington state seal in the center. The words "The Seal of the State of Washington" encircle the seal. Beneath the figure of Washington appears "1889," the year of Washington statehood.
Scott 2005 Specialized Catalogue of U.S. Stamps and Covers
SHG Resources (http://www.shgresources.com/wa/symbols/flag/)