From 1936 to 1942, the BEP used $5 Series of 1934A face plate 307 as a Series of 1934 master plate, altered it into a Series of 1934A master plate, and then finished it as a 1934A production plate. The BEP’s transition in 1938 to Series of 1934A plates was the crucial event that altered the course of plate 307. The 1934As heralded the use of macro plate serials on intaglio currency printing plates. In late 1937, the BEP fulfilled the request of Secret Service officials, whose field officers found it difficult to read the small, or micro, plate serials then being used. The BEP made the plate serials more legible by increasing the size of the numerals; macros appeared almost twice the size of micros.

The BEP utilized the single difference between 1934 and 1934A intaglio faces—the A in 1934A—to simplify production of 1934A faces. They simply etched As into 1934 plates by the same process used to add plate serials to finished plates. They bypassed the need to produce 1934A master intaglio dies and could proceed directly to electrolytic platemaking of 1934A plates.
 

Face plate 307 was started on April 6, 1936, and was immediately used as the master plate for making other 1934 plates. In January 1938, it was altered it into a 1934A master plate for making 1934A plates. It was used as the 1934A master until 1942, when platemakers certified it as a production plate on July 3, and finished it with macro 307 plate serials, alongside contemporary macro plates with serials in the 1660s. It was sent to the plate vault and logged to the pressroom for seven pressruns from July 9, 1942, to June 3, 1943. All 307 sheets have macro backs and K-A block serials. The BEP canceled face 307 on June 19, 1943, after six fruitful years of service