You see it often in banknotes and certificates, holograms are used as a security mark
Official software is secured with holograms, but in stamps it's not that common.
|Holograms used in euro money|
Such a security mark is not really necessary for stamps and mostly the value of a stamp is too low to invest in such a marks.
The only reason for holograms on stamps, is to "show off", to have a "special issue"...
Briefly, to make collectors pay extra.
But it's a given fact, holograms are attractive.
A hologram is a word with greek roots : holograph : hólos (the whole) and graphein (to write, to draw).
So it's a way to write print a whole image.
What is a hologram in fact?
It's not easy to describe it in an easy way, but let's try.
When looking through a window, all waves coming from the window to the retina in your eye. The combination of those waves make us see a 3D image.
Using certain optical (and physical) techniques, a 'photograph' can be made of a certain moment in this cyclus of waves. The image itself is not 3D, but with the use of light (or laserlight) the 'idea' of waves can be reconstructed.
When waves comes from different directions, the 3D image becomes more realistic and 'deeper';
In a hologram, the natural light is reconstructed and gives us the 3D view again.
The larger the holgram is, the bettter the 3D effect and the 'deeper' the view becomes.
The Hungarian scientist Dennis Gabor discovered the basic idea for holograms in 1948, but it lastet till 1960 until the first hologram was made, by the Americas Upatnieks and Leith. Gabor received the Nobelprice for his discovery, in 1971.
So far the theory, now the stamps ...
First sheet is from Poland, a sheet with 2 stamps, one with a hologram of a butterfly.
|Poland holographic butterfly|
|Poland detail hologram|
Secondly Bhutan, a lot can be said about Bhutani stamps, but they have been a pioneer in emitting special stamps. This is a sheet to commemorate the 25th anniversary of Man' first step on the Moon.
|Bhutan 2 hologram in one sheet|
|Bhutan detail hologram|
There are more holographic stamps to follow