The first two blotters today are from the 1928 files in the GN archives at the Minnesota History Center.
Chief Two Guns White Calf somewhat resembled the face on the buffalo nickel, so Great Northern marketing told the public that the sculptor who designed the nickel used Two Guns as a model. This wasn’t true, but the GN said it so often that Two Guns himself probably believed it.
By 1932, when the next three blotters were issued, GN had incorporated Winold Reiss paintings into much of its marketing. I believe that Reiss also designed the font that used little triangles in the cross bars of letters like A, E, and H.
Since these three blotters are dated February, October, and November of 1932, so other Reiss paintings were probably used on similar blotters for the other months of the year.
GN also put Reiss paintings on monthly calendars in 1932, and it seems likely that each month of the calendar coincided with each blotter.