From the introduction 1 April 1871 postal cards should be fully franked when sent. 

From 1 April 1879 partly franked postal cards could be sent to foreign destinations. The receiver then payed double the amount of the missing franking.

From 1 October 1888 partly franked postal cards could be sent domestic. The receiver then payed double the amount of the missing franking.

From 1 July 1892 unfranked postal cards could be sent to foreign destinations. The receiver then payed double the amount of a letter.

If the postal card was sent against regulations (e.g. with a picture glued on reverse) it should be franked as a letter. The receiver then payed double the amount of a letter minus the franking.