May 1943. Pennsylvania R.R. iron ore docks, Cleveland. "After the ore is weighed in the Hulett unloader it is dropped in the waiting hopper cars below." 4x5 Kodachrome transparency by Jack Delano for the OWI. View full size.

October 1913. Houston, Texas. "Jeff Miller. A young delivery boy for Magnolia Pharmacy. This is especially bad for him as he has recently returned from the Seabrook Reform School where he had spent a year. He would not tell me why he was sent there." View full size. Photograph and caption by Lewis Wickes Hine.

Washington, 1943. "United Nations Fight for Freedom: Colored, white and Chinese Boy Scouts in front of Capitol. They help out by delivering posters to help the war effort." View full size. 4x5 Kodachrome transparency by John Rous for the Office of War Information. What photo expert out there can tell us about the numbers on these Kodachromes -- how and at what point in the manufacturing/ exposure/ developing process they were made, and what they signify.

Vicinity of Washington, D.C. Army balloon circa 1918-1921. View full size. Glass negative from the National Photo Company Collection.

Washington, D.C., 1921. View full size. National Photo Company Collection.

Washington, D.C. "Ingley, Yankees, 1921." View full size. National Photo Co.

Washington, D.C., 1921. From the "Babies" file. View full size. National Photo.