The colour and obliteration trials enabled Rowland Hill to select a red ink for the new stamp and a black one for the cancel.
Introduced in February 1841, the Penny Red was a resounding success.
The Twopenny Blue was also improved. A blue ink developed during the trials made the stamp more resistant to forgery.
A winning pair, these two stamps remained in use for 38 years.
= Additional information
Frame 18
Section
Notice to all postmasters announcing the arrival of the new 1841 stamps and penny envelopes. Specimens were included for comparison against forgeries