Fountain pens became more commonplace than dip pens around the time of the World War I, although early 20th-century schoolchildren were still learning how to write with the older implements.

“Fahrney’s Pens,” the sign in calligraphy reads. Inside, the narrow space with 28-foot ceilings is a cathedral to its acolytes, its objects of worship gleaming under glass counters.

Ross Cameron of Conklin Pens shows a self-filling fountain pen at Fahrney’s Pens on F Street NW. Some millennials embrace the pens, which are undergoing a resurgence. (John Kelly/The Washington ...