Embossed postage stamps have been around almost from the beginning
of stamp production.
In 1847 GB issued the first embossed stamps and was followed mid 19th century by most of the German States.
Schleswig-Holstein 1850, Württemberg 1857,Prussia 1861,Saxony 1863, Bavaria 1867 etc.
I believe that embossing was applied to stamps as a security feature to prevent counterfeiting.
But there isn't a lot of information that I can find and that's why I started this thread hoping that forum members can add to it.
In this post from Rod (who has some info on everything) there is an illustration of a 1910 model embossing press.http://goscf.com/t/65632&whichpage=2
I'm curious as to how modern embossing is done, what type of printing presses are used, is different paper needed and so on.
By about 1900 stamp embossing seems to have petered out although it continued on postal stationery.
Over the years some countries have issued the odd embossed stamp not for security reasons but as an added feature to make the stamp pretty for collectors.