On 22 March 2005, Royal Mail issued a minisheet for the 50th anniversary of the Castle series. Denominations were changed to 50p  for a brown "Carrickfergus Castle" and a dark brown "Windsor Castle", and £1 for a red "Caernarfon Castle" and a blue "Edinburgh Castle". The Dutch printer Enschedé succeeded in using the original dyes to create the new printing material, but for the Windsor Castle stamp digitalization of a 1955 stamp was necessary.