Vertical bar spacings on the back of the $1 and $5  duty plate.

The half of the duty plate that printed the front of the two lower denominations consisted of the denomination numerals, the lines around them, some ornaments, and the denomination spelled out. Obviously this had to be reset every time they changed over from printing one denomination to the other. But the half that printed the back consisted only of the frame and a double-line vertical bar to frame the right side of the Juarez portrait. This invited little attention until Crutchfield Williams pointed out some variation in the spacing of this vertical bar relative to the left side of the frame. The first measurement is the distance between the double-bar and the left frame line. The measurement in parenthesis is the spacing between the two lines that comprise the vertical bar.

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