Plate numbers for SG12
FEBRUARY 1841
12 through 131
FEBRUARY 1852
132 through 177
It was discovered that the red MX cancellations were being removed from the penny black in order that they could be reused. This prompted Rowland Hill initiate the Rainbow trials, whereby different inks and printing techniques were tested in order to overcome this problem. The goal was create an ink which would be more permanent than the ink used to print the stamp. It resulted in only the black MX cancel being used, and red-brown printing ink, the combination of which clearly showed the cancel.