What do you collect as a philatelist - part 3

Some people prefer to collect rather unusual philatelic material. Included on these groups are the errors, the freak stamps, special overprint stamps and some material which can not be considered as philatelic material. The last material normally called cinderela.
I will go through each material to give an explanation of what they really mean.

Error or Freak Stamps
As the title implies, the material that are included on these category are the "wrong" material. There are various mistake on the philatelic material. The mistake could come from a misprint, but by accident the misprinted stamp is being used and sold through the post office.
The misprint could be in the form of wrong colour print, missing colour, shifted print, undetected damage on the printing plate, inverted picture, misperforate or imperforate stamps.
All the stamps with these mistakes should not have been sold or distributed in the market, but again the postal office is run by only human, and of course mistake does happen. So then this material is out in the market. It is a rather specialize material and not very easy to collect.

Overprinted Stamps
There are occasion where the post office decides that they want to re-issue some stamps with different value. There are various reason for this action, one is that they have too much unsold printed stamps of a certain theme. The other reason is the is a special celebration and the time to design a new stamps is too short. In the old days, these method of overprint is also used to change the value of the stamps, e.g. during the conversion of Indonesian currency in 1966 from Rp. 1,000 to Rp. 1.00. The stamps at that time was overprinted with a new value to reflect the changes of currency value.
There are also an overprinted process which is done to indicate that the stamp is a special stamps. A good example of this is the overprint "specimen" which normally only used on stamps that is given to the UPU (Universal Postage Union) for the sample of the issued stamps. Or the overprint "official" or "military" which indicates that the stamps in to be used only by a certain organization.
The overprint method is also used to change the country's name. A lot of these stamps existed during the end period of collonial time. There were some Indonesian stamps from 1940 to 1945 which are issued by using the old Dutch stamps with some overprint to indicate that the stamps are now belong to the Indonesian government.

Cinderela
Cinderela is not an official stamps. These are considered as toys, but imitating the form of stamps. Cinderela exist in the form of food coupon, promotional material from companies and a few other specialize situation.
Most of the time, people are collecting these stamps because of the picture in it which is very similar to the theme of their stamp collection. However, some of these cinderela can be very expensive because it is very scarce.