Intaglio Issues, Engraved by Pierre Gandon
With the Intaglio (or in French, Taille Douce) process, the design is first cut into a die (the piece of metal into which the engraved image of the stamp is cut). The die is then used to make a roller, which is used to multiply the design as many times as needed on to the printing base. This printing base is then used to print on paper.
The 25F stamp was used for American troops in France, for telegraphs back to the U.S.A.