The Penny Blue is frequently mistaken for a postage stamp of Britain.

It is from a series of proof impressions which were made at the time Rowland Hill was looking at the new colours which were to be used for the stamps which were to replace the Penny Black and the original 1840 issue of the Two pence Blue.

At the beginning of December 1840, Rowland Hill wished to see what the stamps would look like in the new colours and requested, (in sheet form), examples in the red brown which was to be used for the new one penny stamp as well as two sheets in blue as the choice of colour had not yet been made.

Rowland Hill chose the full deep blue colour for the two pence stamp.

This was more critical in the early days of stamp production where metal (and sometimes stone or even wooden plates) were used to make the stamp impression, and some inks caused undue wear on the plates.