Illustrated below are two stamps. No 1 is the 1 Penny (black and carmine-red) of Rarotonga issued in 1920 when the island was a dependency of New Zealand. It shows the Wharf at Avarua. The stamp is more highly valued lightly used than mint.
The second example is the Cook Islands 6 Pence "White Tern or Torea" this was issued between 1896 and 1900 in values of a halfpenny to 1 Shilling. During the printing some of the values were re-issued with slightly different colours. The sixpence shown below was issued in purple in 1898 and again in 1900 in bright purple, this is the 1900 issue. Also more highly valued lightly used.