The printing plate of the 1-cent Franklin was originally produced by the National Bank Note Company in 1869. When it was reused by American Bank Note Company a decade later, it carried Continental Bank Note Company’s identification marks or ‘secret marks’ that had distinguished its 1873 printings. On the 1-cent Franklin, the mark is the small horizontal dash in the largest of the pearls immediately to the left of the ‘1’ at the bottom of the stamp. CBNCo most likely etched this mark on each stamp design in the plate using a small amount of acid.
Continental Bank Note Company, along with other printing and engraving firms, had been consolidated into the American Bank Note Company in 1879. When ABNCo took over the contract to print U.S. stamps and acquired all printing plates held by CBNCo, it differentiated its printing of the 1-cent Franklin of the 1879 Issue by using soft, porous paper. CBNCo had used white wove paper.
The mail rate for a postcard was one cent in 1879. The 1-cent Franklin (as a single use) could have paid the card rate or, in combination with other denominations, higher rates. Approximately 590 million stamps of the 1-cent Franklin were printed by American Bank Note Company.