This card is an example of the very rare pink shade variety of the Fipex postal card. The verdict is probably still not out on whether this is actually a different ink, or if the ordinary ink somehow became thinned or started to run dry in the press inkwell at the time of printing.
If you want to 'hunt' for this rare and elusive beast, it helps to make your own Fipex 'Prexie Tester' as shown below. The normal Fipex card is quite common in mint condition, and trimming the test card along one of the diagonals of the vignette triangle and adding the prexies makes for a useful overlay tool. This helps to make a positive ID.
The normal color of the Fipex card resembles the 2-Cent prexie issue of 1938. The scarce rose-pink shade should be somewhere in between the color of the prexies, but the rare true pink shade closely resembles the color of the 9-Cent value.
As you can see below, this one doesn't get any 'pinker'. Interestingly enough, this card
also exhibits offset doubling of the black overprinting as well.
